Merge pull request #6196 from hugovk/cleanup-names

Cleanup: adjust names

Tests/helper.py

@@ -324,7 +324,7 @@ def is_mingw():
     return sysconfig.get_platform() == "mingw"
 
 
-class cached_property:
+class CachedProperty:
     def __init__(self, func):
         self.func = func
 

Tests/test_box_blur.py

@@ -25,7 +25,7 @@ def box_blur(image, radius=1, n=1):
     return image._new(image.im.box_blur(radius, n))
 
 
-def assertImage(im, data, delta=0):
+def assert_image(im, data, delta=0):
     it = iter(im.getdata())
     for data_row in data:
         im_row = [next(it) for _ in range(im.size[0])]
@@ -35,12 +35,12 @@ def assertImage(im, data, delta=0):
         next(it)
 
 
-def assertBlur(im, radius, data, passes=1, delta=0):
+def assert_blur(im, radius, data, passes=1, delta=0):
     # check grayscale image
-    assertImage(box_blur(im, radius, passes), data, delta)
+    assert_image(box_blur(im, radius, passes), data, delta)
     rgba = Image.merge("RGBA", (im, im, im, im))
     for band in box_blur(rgba, radius, passes).split():
-        assertImage(band, data, delta)
+        assert_image(band, data, delta)
 
 
 def test_color_modes():
@@ -64,7 +64,7 @@ def test_color_modes():
 
 
 def test_radius_0():
-    assertBlur(
+    assert_blur(
         sample,
         0,
         [
@@ -80,7 +80,7 @@ def test_radius_0():
 
 
 def test_radius_0_02():
-    assertBlur(
+    assert_blur(
         sample,
         0.02,
         [
@@ -97,7 +97,7 @@ def test_radius_0_02():
 
 
 def test_radius_0_05():
-    assertBlur(
+    assert_blur(
         sample,
         0.05,
         [
@@ -114,7 +114,7 @@ def test_radius_0_05():
 
 
 def test_radius_0_1():
-    assertBlur(
+    assert_blur(
         sample,
         0.1,
         [
@@ -131,7 +131,7 @@ def test_radius_0_1():
 
 
 def test_radius_0_5():
-    assertBlur(
+    assert_blur(
         sample,
         0.5,
         [
@@ -148,7 +148,7 @@ def test_radius_0_5():
 
 
 def test_radius_1():
-    assertBlur(
+    assert_blur(
         sample,
         1,
         [
@@ -165,7 +165,7 @@ def test_radius_1():
 
 
 def test_radius_1_5():
-    assertBlur(
+    assert_blur(
         sample,
         1.5,
         [
@@ -182,7 +182,7 @@ def test_radius_1_5():
 
 
 def test_radius_bigger_then_half():
-    assertBlur(
+    assert_blur(
         sample,
         3,
         [
@@ -199,7 +199,7 @@ def test_radius_bigger_then_half():
 
 
 def test_radius_bigger_then_width():
-    assertBlur(
+    assert_blur(
         sample,
         10,
         [
@@ -214,7 +214,7 @@ def test_radius_bigger_then_width():
 
 
 def test_extreme_large_radius():
-    assertBlur(
+    assert_blur(
         sample,
         600,
         [
@@ -229,7 +229,7 @@ def test_extreme_large_radius():
 
 
 def test_two_passes():
-    assertBlur(
+    assert_blur(
         sample,
         1,
         [
@@ -247,7 +247,7 @@ def test_two_passes():
 
 
 def test_three_passes():
-    assertBlur(
+    assert_blur(
         sample,
         1,
         [

Tests/test_color_lut.py

@@ -15,27 +15,27 @@ except ImportError:
 class TestColorLut3DCoreAPI:
     def generate_identity_table(self, channels, size):
         if isinstance(size, tuple):
-            size1D, size2D, size3D = size
+            size_1d, size_2d, size_3d = size
         else:
-            size1D, size2D, size3D = (size, size, size)
+            size_1d, size_2d, size_3d = (size, size, size)
 
         table = [
             [
-                r / (size1D - 1) if size1D != 1 else 0,
+                r / (size_1d - 1) if size_1d != 1 else 0,
-                g / (size2D - 1) if size2D != 1 else 0,
+                g / (size_2d - 1) if size_2d != 1 else 0,
-                b / (size3D - 1) if size3D != 1 else 0,
+                b / (size_3d - 1) if size_3d != 1 else 0,
-                r / (size1D - 1) if size1D != 1 else 0,
+                r / (size_1d - 1) if size_1d != 1 else 0,
-                g / (size2D - 1) if size2D != 1 else 0,
+                g / (size_2d - 1) if size_2d != 1 else 0,
             ][:channels]
-            for b in range(size3D)
+            for b in range(size_3d)
-            for g in range(size2D)
+            for g in range(size_2d)
-            for r in range(size1D)
+            for r in range(size_1d)
         ]
         return (
             channels,
-            size1D,
+            size_1d,
-            size2D,
+            size_2d,
-            size3D,
+            size_3d,
             [item for sublist in table for item in sublist],
         )
 

Tests/test_decompression_bomb.py

@@ -78,7 +78,7 @@ class TestDecompressionCrop:
     def teardown_class(self):
         Image.MAX_IMAGE_PIXELS = ORIGINAL_LIMIT
 
-    def testEnlargeCrop(self):
+    def test_enlarge_crop(self):
         # Crops can extend the extents, therefore we should have the
         # same decompression bomb warnings on them.
         with hopper() as src:

Tests/test_file_gif.py

@@ -799,31 +799,31 @@ def test_zero_comment_subblocks():
 def test_version(tmp_path):
     out = str(tmp_path / "temp.gif")
 
-    def assertVersionAfterSave(im, version):
+    def assert_version_after_save(im, version):
         im.save(out)
         with Image.open(out) as reread:
             assert reread.info["version"] == version
 
     # Test that GIF87a is used by default
     im = Image.new("L", (100, 100), "#000")
-    assertVersionAfterSave(im, b"GIF87a")
+    assert_version_after_save(im, b"GIF87a")
 
     # Test setting the version to 89a
     im = Image.new("L", (100, 100), "#000")
     im.info["version"] = b"89a"
-    assertVersionAfterSave(im, b"GIF89a")
+    assert_version_after_save(im, b"GIF89a")
 
     # Test that adding a GIF89a feature changes the version
     im.info["transparency"] = 1
-    assertVersionAfterSave(im, b"GIF89a")
+    assert_version_after_save(im, b"GIF89a")
 
     # Test that a GIF87a image is also saved in that format
     with Image.open("Tests/images/test.colors.gif") as im:
-        assertVersionAfterSave(im, b"GIF87a")
+        assert_version_after_save(im, b"GIF87a")
 
         # Test that a GIF89a image is also saved in that format
         im.info["version"] = b"GIF89a"
-        assertVersionAfterSave(im, b"GIF87a")
+        assert_version_after_save(im, b"GIF87a")
 
 
 def test_append_images(tmp_path):
@@ -838,10 +838,10 @@ def test_append_images(tmp_path):
         assert reread.n_frames == 3
 
     # Tests appending using a generator
-    def imGenerator(ims):
+    def im_generator(ims):
         yield from ims
 
-    im.save(out, save_all=True, append_images=imGenerator(ims))
+    im.save(out, save_all=True, append_images=im_generator(ims))
 
     with Image.open(out) as reread:
         assert reread.n_frames == 3

Tests/test_file_mpo.py

@@ -145,10 +145,10 @@ def test_mp_attribute():
     for test_file in test_files:
         with Image.open(test_file) as im:
             mpinfo = im._getmp()
-        frameNumber = 0
+        frame_number = 0
         for mpentry in mpinfo[0xB002]:
             mpattr = mpentry["Attribute"]
-            if frameNumber:
+            if frame_number:
                 assert not mpattr["RepresentativeImageFlag"]
             else:
                 assert mpattr["RepresentativeImageFlag"]
@@ -157,7 +157,7 @@ def test_mp_attribute():
             assert mpattr["ImageDataFormat"] == "JPEG"
             assert mpattr["MPType"] == "Multi-Frame Image: (Disparity)"
             assert mpattr["Reserved"] == 0
-            frameNumber += 1
+            frame_number += 1
 
 
 def test_seek():

Tests/test_file_pdf.py

@@ -131,10 +131,10 @@ def test_save_all(tmp_path):
         assert os.path.getsize(outfile) > 0
 
         # Test appending using a generator
-        def imGenerator(ims):
+        def im_generator(ims):
             yield from ims
 
-        im.save(outfile, save_all=True, append_images=imGenerator(ims))
+        im.save(outfile, save_all=True, append_images=im_generator(ims))
 
     assert os.path.isfile(outfile)
     assert os.path.getsize(outfile) > 0
@@ -253,9 +253,9 @@ def test_pdf_append(tmp_path):
         check_pdf_pages_consistency(pdf)
 
     # append two images
-    mode_CMYK = hopper("CMYK")
+    mode_cmyk = hopper("CMYK")
-    mode_P = hopper("P")
+    mode_p = hopper("P")
-    mode_CMYK.save(pdf_filename, append=True, save_all=True, append_images=[mode_P])
+    mode_cmyk.save(pdf_filename, append=True, save_all=True, append_images=[mode_p])
 
     # open the PDF again, check pages and info again
     with PdfParser.PdfParser(pdf_filename) as pdf:

Tests/test_file_tiff.py

@@ -151,14 +151,14 @@ class TestFileTiff:
             assert im.info["dpi"] == (71.0, 71.0)
 
     @pytest.mark.parametrize(
-        "resolutionUnit, dpi",
+        "resolution_unit, dpi",
         [(None, 72.8), (2, 72.8), (3, 184.912)],
     )
-    def test_load_float_dpi(self, resolutionUnit, dpi):
+    def test_load_float_dpi(self, resolution_unit, dpi):
         with Image.open(
-            "Tests/images/hopper_float_dpi_" + str(resolutionUnit) + ".tif"
+            "Tests/images/hopper_float_dpi_" + str(resolution_unit) + ".tif"
         ) as im:
-            assert im.tag_v2.get(RESOLUTION_UNIT) == resolutionUnit
+            assert im.tag_v2.get(RESOLUTION_UNIT) == resolution_unit
             assert im.info["dpi"] == (dpi, dpi)
 
     def test_save_float_dpi(self, tmp_path):
@@ -655,11 +655,11 @@ class TestFileTiff:
             assert reread.n_frames == 3
 
         # Test appending using a generator
-        def imGenerator(ims):
+        def im_generator(ims):
             yield from ims
 
         mp = BytesIO()
-        im.save(mp, format="TIFF", save_all=True, append_images=imGenerator(ims))
+        im.save(mp, format="TIFF", save_all=True, append_images=im_generator(ims))
 
         mp.seek(0, os.SEEK_SET)
         with Image.open(mp) as reread:

Tests/test_file_tiff_metadata.py

@@ -28,26 +28,26 @@ def test_rt_metadata(tmp_path):
     # For text items, we still have to decode('ascii','replace') because
     # the tiff file format can't take 8 bit bytes in that field.
 
-    basetextdata = "This is some arbitrary metadata for a text field"
+    base_text_data = "This is some arbitrary metadata for a text field"
-    bindata = basetextdata.encode("ascii") + b" \xff"
+    bin_data = base_text_data.encode("ascii") + b" \xff"
-    textdata = basetextdata + " " + chr(255)
+    text_data = base_text_data + " " + chr(255)
-    reloaded_textdata = basetextdata + " ?"
+    reloaded_text_data = base_text_data + " ?"
-    floatdata = 12.345
+    float_data = 12.345
-    doubledata = 67.89
+    double_data = 67.89
     info = TiffImagePlugin.ImageFileDirectory()
 
     ImageJMetaData = TAG_IDS["ImageJMetaData"]
     ImageJMetaDataByteCounts = TAG_IDS["ImageJMetaDataByteCounts"]
     ImageDescription = TAG_IDS["ImageDescription"]
 
-    info[ImageJMetaDataByteCounts] = len(bindata)
+    info[ImageJMetaDataByteCounts] = len(bin_data)
-    info[ImageJMetaData] = bindata
+    info[ImageJMetaData] = bin_data
-    info[TAG_IDS["RollAngle"]] = floatdata
+    info[TAG_IDS["RollAngle"]] = float_data
     info.tagtype[TAG_IDS["RollAngle"]] = 11
-    info[TAG_IDS["YawAngle"]] = doubledata
+    info[TAG_IDS["YawAngle"]] = double_data
     info.tagtype[TAG_IDS["YawAngle"]] = 12
 
-    info[ImageDescription] = textdata
+    info[ImageDescription] = text_data
 
     f = str(tmp_path / "temp.tif")
 
@@ -55,28 +55,28 @@ def test_rt_metadata(tmp_path):
 
     with Image.open(f) as loaded:
 
-        assert loaded.tag[ImageJMetaDataByteCounts] == (len(bindata),)
+        assert loaded.tag[ImageJMetaDataByteCounts] == (len(bin_data),)
-        assert loaded.tag_v2[ImageJMetaDataByteCounts] == (len(bindata),)
+        assert loaded.tag_v2[ImageJMetaDataByteCounts] == (len(bin_data),)
 
-        assert loaded.tag[ImageJMetaData] == bindata
+        assert loaded.tag[ImageJMetaData] == bin_data
-        assert loaded.tag_v2[ImageJMetaData] == bindata
+        assert loaded.tag_v2[ImageJMetaData] == bin_data
 
-        assert loaded.tag[ImageDescription] == (reloaded_textdata,)
+        assert loaded.tag[ImageDescription] == (reloaded_text_data,)
-        assert loaded.tag_v2[ImageDescription] == reloaded_textdata
+        assert loaded.tag_v2[ImageDescription] == reloaded_text_data
 
         loaded_float = loaded.tag[TAG_IDS["RollAngle"]][0]
-        assert round(abs(loaded_float - floatdata), 5) == 0
+        assert round(abs(loaded_float - float_data), 5) == 0
         loaded_double = loaded.tag[TAG_IDS["YawAngle"]][0]
-        assert round(abs(loaded_double - doubledata), 7) == 0
+        assert round(abs(loaded_double - double_data), 7) == 0
 
     # check with 2 element ImageJMetaDataByteCounts, issue #2006
 
-    info[ImageJMetaDataByteCounts] = (8, len(bindata) - 8)
+    info[ImageJMetaDataByteCounts] = (8, len(bin_data) - 8)
     img.save(f, tiffinfo=info)
     with Image.open(f) as loaded:
 
-        assert loaded.tag[ImageJMetaDataByteCounts] == (8, len(bindata) - 8)
+        assert loaded.tag[ImageJMetaDataByteCounts] == (8, len(bin_data) - 8)
-        assert loaded.tag_v2[ImageJMetaDataByteCounts] == (8, len(bindata) - 8)
+        assert loaded.tag_v2[ImageJMetaDataByteCounts] == (8, len(bin_data) - 8)
 
 
 def test_read_metadata():
@@ -356,7 +356,7 @@ def test_empty_values():
     assert 33432 in info
 
 
-def test_PhotoshopInfo(tmp_path):
+def test_photoshop_info(tmp_path):
     with Image.open("Tests/images/issue_2278.tif") as im:
         assert len(im.tag_v2[34377]) == 70
         assert isinstance(im.tag_v2[34377], bytes)

Tests/test_file_webp_animated.py

@@ -90,14 +90,14 @@ def test_write_animation_RGB(tmp_path):
             check(temp_file1)
 
             # Tests appending using a generator
-            def imGenerator(ims):
+            def im_generator(ims):
                 yield from ims
 
             temp_file2 = str(tmp_path / "temp_generator.webp")
             frame1.copy().save(
                 temp_file2,
                 save_all=True,
-                append_images=imGenerator([frame2]),
+                append_images=im_generator([frame2]),
                 lossless=True,
             )
             check(temp_file2)

Tests/test_image_copy.py

@@ -6,8 +6,8 @@ from .helper import hopper
 
 
 def test_copy():
-    croppedCoordinates = (10, 10, 20, 20)
+    cropped_coordinates = (10, 10, 20, 20)
-    croppedSize = (10, 10)
+    cropped_size = (10, 10)
     for mode in "1", "P", "L", "RGB", "I", "F":
         # Internal copy method
         im = hopper(mode)
@@ -23,15 +23,15 @@ def test_copy():
 
         # Internal copy method on a cropped image
         im = hopper(mode)
-        out = im.crop(croppedCoordinates).copy()
+        out = im.crop(cropped_coordinates).copy()
         assert out.mode == im.mode
-        assert out.size == croppedSize
+        assert out.size == cropped_size
 
         # Python's copy method on a cropped image
         im = hopper(mode)
-        out = copy.copy(im.crop(croppedCoordinates))
+        out = copy.copy(im.crop(cropped_coordinates))
         assert out.mode == im.mode
-        assert out.size == croppedSize
+        assert out.size == cropped_size
 
 
 def test_copy_zero():

Tests/test_image_filter.py

@@ -99,10 +99,10 @@ def test_rankfilter_properties():
 
 
 def test_builtinfilter_p():
-    builtinFilter = ImageFilter.BuiltinFilter()
+    builtin_filter = ImageFilter.BuiltinFilter()
 
     with pytest.raises(ValueError):
-        builtinFilter.filter(hopper("P"))
+        builtin_filter.filter(hopper("P"))
 
 
 def test_kernel_not_enough_coefficients():

Tests/test_image_paste.py

@@ -1,6 +1,6 @@
 from PIL import Image
 
-from .helper import assert_image_equal, cached_property
+from .helper import CachedProperty, assert_image_equal
 
 
 class TestImagingPaste:
@@ -34,7 +34,7 @@ class TestImagingPaste:
         im.paste(im2, mask)
         self.assert_9points_image(im, expected)
 
-    @cached_property
+    @CachedProperty
     def mask_1(self):
         mask = Image.new("1", (self.size, self.size))
         px = mask.load()
@@ -43,11 +43,11 @@ class TestImagingPaste:
                 px[y, x] = (x + y) % 2
         return mask
 
-    @cached_property
+    @CachedProperty
     def mask_L(self):
         return self.gradient_L.transpose(Image.Transpose.ROTATE_270)
 
-    @cached_property
+    @CachedProperty
     def gradient_L(self):
         gradient = Image.new("L", (self.size, self.size))
         px = gradient.load()
@@ -56,7 +56,7 @@ class TestImagingPaste:
                 px[y, x] = (x + y) % 255
         return gradient
 
-    @cached_property
+    @CachedProperty
     def gradient_RGB(self):
         return Image.merge(
             "RGB",
@@ -67,7 +67,7 @@ class TestImagingPaste:
             ],
         )
 
-    @cached_property
+    @CachedProperty
     def gradient_LA(self):
         return Image.merge(
             "LA",
@@ -77,7 +77,7 @@ class TestImagingPaste:
             ],
         )
 
-    @cached_property
+    @CachedProperty
     def gradient_RGBA(self):
         return Image.merge(
             "RGBA",
@@ -89,7 +89,7 @@ class TestImagingPaste:
             ],
         )
 
-    @cached_property
+    @CachedProperty
     def gradient_RGBa(self):
         return Image.merge(
             "RGBa",

Tests/test_imagefile.py

@@ -35,9 +35,9 @@ class TestImageFile:
 
             parser = ImageFile.Parser()
             parser.feed(data)
-            imOut = parser.close()
+            im_out = parser.close()
 
-            return im, imOut
+            return im, im_out
 
         assert_image_equal(*roundtrip("BMP"))
         im1, im2 = roundtrip("GIF")

Tests/test_imagemorph.py

@@ -48,8 +48,8 @@ def img_string_normalize(im):
     return img_to_string(string_to_img(im))
 
 
-def assert_img_equal_img_string(A, Bstring):
+def assert_img_equal_img_string(a, b_string):
-    assert img_to_string(A) == img_string_normalize(Bstring)
+    assert img_to_string(a) == img_string_normalize(b_string)
 
 
 def test_str_to_img():

Tests/test_imagepath.py

@@ -174,7 +174,7 @@ def test_overflow_segfault():
     # through to the sequence. Seeing this on 32-bit Windows.
     with pytest.raises((TypeError, MemoryError)):
         # post patch, this fails with a memory error
-        x = evil()
+        x = Evil()
 
         # This fails due to the invalid malloc above,
         # and segfaults
@@ -182,7 +182,7 @@ def test_overflow_segfault():
             x[i] = b"0" * 16
 
 
-class evil:
+class Evil:
     def __init__(self):
         self.corrupt = Image.core.path(0x4000000000000000)
 

Tests/test_imagesequence.py

@@ -65,12 +65,12 @@ def test_libtiff():
 
 def test_consecutive():
     with Image.open("Tests/images/multipage.tiff") as im:
-        firstFrame = None
+        first_frame = None
         for frame in ImageSequence.Iterator(im):
-            if firstFrame is None:
+            if first_frame is None:
-                firstFrame = frame.copy()
+                first_frame = frame.copy()
         for frame in ImageSequence.Iterator(im):
-            assert_image_equal(frame, firstFrame)
+            assert_image_equal(frame, first_frame)
             break
 
 

Tests/test_mode_i16.py

@@ -26,51 +26,51 @@ def test_basic(tmp_path):
 
     def basic(mode):
 
-        imIn = original.convert(mode)
+        im_in = original.convert(mode)
-        verify(imIn)
+        verify(im_in)
 
-        w, h = imIn.size
+        w, h = im_in.size
 
-        imOut = imIn.copy()
+        im_out = im_in.copy()
-        verify(imOut)  # copy
+        verify(im_out)  # copy
 
-        imOut = imIn.transform((w, h), Image.Transform.EXTENT, (0, 0, w, h))
+        im_out = im_in.transform((w, h), Image.Transform.EXTENT, (0, 0, w, h))
-        verify(imOut)  # transform
+        verify(im_out)  # transform
 
         filename = str(tmp_path / "temp.im")
-        imIn.save(filename)
+        im_in.save(filename)
 
-        with Image.open(filename) as imOut:
+        with Image.open(filename) as im_out:
 
-            verify(imIn)
+            verify(im_in)
-            verify(imOut)
+            verify(im_out)
 
-        imOut = imIn.crop((0, 0, w, h))
+        im_out = im_in.crop((0, 0, w, h))
-        verify(imOut)
+        verify(im_out)
 
-        imOut = Image.new(mode, (w, h), None)
+        im_out = Image.new(mode, (w, h), None)
-        imOut.paste(imIn.crop((0, 0, w // 2, h)), (0, 0))
+        im_out.paste(im_in.crop((0, 0, w // 2, h)), (0, 0))
-        imOut.paste(imIn.crop((w // 2, 0, w, h)), (w // 2, 0))
+        im_out.paste(im_in.crop((w // 2, 0, w, h)), (w // 2, 0))
 
-        verify(imIn)
+        verify(im_in)
-        verify(imOut)
+        verify(im_out)
 
-        imIn = Image.new(mode, (1, 1), 1)
+        im_in = Image.new(mode, (1, 1), 1)
-        assert imIn.getpixel((0, 0)) == 1
+        assert im_in.getpixel((0, 0)) == 1
 
-        imIn.putpixel((0, 0), 2)
+        im_in.putpixel((0, 0), 2)
-        assert imIn.getpixel((0, 0)) == 2
+        assert im_in.getpixel((0, 0)) == 2
 
         if mode == "L":
             maximum = 255
         else:
             maximum = 32767
 
-        imIn = Image.new(mode, (1, 1), 256)
+        im_in = Image.new(mode, (1, 1), 256)
-        assert imIn.getpixel((0, 0)) == min(256, maximum)
+        assert im_in.getpixel((0, 0)) == min(256, maximum)
 
-        imIn.putpixel((0, 0), 512)
+        im_in.putpixel((0, 0), 512)
-        assert imIn.getpixel((0, 0)) == min(512, maximum)
+        assert im_in.getpixel((0, 0)) == min(512, maximum)
 
     basic("L")
 

Tests/test_util.py

@@ -8,7 +8,7 @@ def test_is_path():
     fp = "filename.ext"
 
     # Act
-    it_is = _util.isPath(fp)
+    it_is = _util.is_path(fp)
 
     # Assert
     assert it_is
@@ -21,7 +21,7 @@ def test_path_obj_is_path():
     test_path = Path("filename.ext")
 
     # Act
-    it_is = _util.isPath(test_path)
+    it_is = _util.is_path(test_path)
 
     # Assert
     assert it_is
@@ -33,7 +33,7 @@ def test_is_not_path(tmp_path):
         pass
 
     # Act
-    it_is_not = _util.isPath(fp)
+    it_is_not = _util.is_path(fp)
 
     # Assert
     assert not it_is_not
@@ -44,7 +44,7 @@ def test_is_directory():
     directory = "Tests"
 
     # Act
-    it_is = _util.isDirectory(directory)
+    it_is = _util.is_directory(directory)
 
     # Assert
     assert it_is
@@ -55,7 +55,7 @@ def test_is_not_directory():
     text = "abc"
 
     # Act
-    it_is_not = _util.isDirectory(text)
+    it_is_not = _util.is_directory(text)
 
     # Assert
     assert not it_is_not
@@ -65,7 +65,7 @@ def test_deferred_error():
     # Arrange
 
     # Act
-    thing = _util.deferred_error(ValueError("Some error text"))
+    thing = _util.DeferredError(ValueError("Some error text"))
 
     # Assert
     with pytest.raises(ValueError):

src/PIL/GdImageFile.py

@@ -54,20 +54,25 @@ class GdImageFile(ImageFile.ImageFile):
         self.mode = "L"  # FIXME: "P"
         self._size = i16(s, 2), i16(s, 4)
 
-        trueColor = s[6]
+        true_color = s[6]
-        trueColorOffset = 2 if trueColor else 0
+        true_color_offset = 2 if true_color else 0
 
         # transparency index
-        tindex = i32(s, 7 + trueColorOffset)
+        tindex = i32(s, 7 + true_color_offset)
         if tindex < 256:
             self.info["transparency"] = tindex
 
         self.palette = ImagePalette.raw(
-            "XBGR", s[7 + trueColorOffset + 4 : 7 + trueColorOffset + 4 + 256 * 4]
+            "XBGR", s[7 + true_color_offset + 4 : 7 + true_color_offset + 4 + 256 * 4]
         )
 
         self.tile = [
-            ("raw", (0, 0) + self.size, 7 + trueColorOffset + 4 + 256 * 4, ("L", 0, 1))
+            (
+                "raw",
+                (0, 0) + self.size,
+                7 + true_color_offset + 4 + 256 * 4,
+                ("L", 0, 1),
+            )
         ]
 
 

src/PIL/GifImagePlugin.py

@@ -883,10 +883,10 @@ def _get_palette_bytes(im):
     return im.palette.palette
 
 
-def _get_background(im, infoBackground):
+def _get_background(im, info_background):
     background = 0
-    if infoBackground:
+    if info_background:
-        background = infoBackground
+        background = info_background
         if isinstance(background, tuple):
             # WebPImagePlugin stores an RGBA value in info["background"]
             # So it must be converted to the same format as GifImagePlugin's

src/PIL/Image.py

@@ -51,7 +51,7 @@ except ImportError:
 from . import ImageMode, TiffTags, UnidentifiedImageError, __version__, _plugins
 from ._binary import i32le, o32be, o32le
 from ._deprecate import deprecate
-from ._util import deferred_error, isPath
+from ._util import DeferredError, is_path
 
 
 def __getattr__(name):
@@ -108,7 +108,7 @@ try:
         )
 
 except ImportError as v:
-    core = deferred_error(ImportError("The _imaging C module is not installed."))
+    core = DeferredError(ImportError("The _imaging C module is not installed."))
     # Explanations for ways that we know we might have an import error
     if str(v).startswith("Module use of python"):
         # The _imaging C module is present, but not compiled for
@@ -577,7 +577,7 @@ class Image:
         # Instead of simply setting to None, we're setting up a
         # deferred error that will better explain that the core image
         # object is gone.
-        self.im = deferred_error(ValueError("Operation on closed image"))
+        self.im = DeferredError(ValueError("Operation on closed image"))
 
     def _copy(self):
         self.load()
@@ -2215,7 +2215,7 @@ class Image:
         if isinstance(fp, Path):
             filename = str(fp)
             open_fp = True
-        elif isPath(fp):
+        elif is_path(fp):
             filename = fp
             open_fp = True
         elif fp == sys.stdout:
@@ -2223,7 +2223,7 @@ class Image:
                 fp = sys.stdout.buffer
             except AttributeError:
                 pass
-        if not filename and hasattr(fp, "name") and isPath(fp.name):
+        if not filename and hasattr(fp, "name") and is_path(fp.name):
             # only set the name for metadata purposes
             filename = fp.name
 
@@ -3029,7 +3029,7 @@ def open(fp, mode="r", formats=None):
     filename = ""
     if isinstance(fp, Path):
         filename = str(fp.resolve())
-    elif isPath(fp):
+    elif is_path(fp):
         filename = fp
 
     if filename:

src/PIL/ImageCms.py

@@ -27,9 +27,9 @@ try:
 except ImportError as ex:
     # Allow error import for doc purposes, but error out when accessing
     # anything in core.
-    from ._util import deferred_error
+    from ._util import DeferredError
 
-    _imagingcms = deferred_error(ex)
+    _imagingcms = DeferredError(ex)
 
 DESCRIPTION = """
 pyCMS

src/PIL/ImageDraw.py

@@ -197,18 +197,18 @@ class ImageDraw:
                     if width > 8:
                         # Cover potential gaps between the line and the joint
                         if flipped:
-                            gapCoords = [
+                            gap_coords = [
                                 coord_at_angle(point, angles[0] + 90),
                                 point,
                                 coord_at_angle(point, angles[1] + 90),
                             ]
                         else:
-                            gapCoords = [
+                            gap_coords = [
                                 coord_at_angle(point, angles[0] - 90),
                                 point,
                                 coord_at_angle(point, angles[1] - 90),
                             ]
-                        self.line(gapCoords, fill, width=3)
+                        self.line(gap_coords, fill, width=3)
 
     def shape(self, shape, fill=None, outline=None):
         """(Experimental) Draw a shape."""

src/PIL/ImageFile.py

@@ -33,7 +33,7 @@ import struct
 import sys
 
 from . import Image
-from ._util import isPath
+from ._util import is_path
 
 MAXBLOCK = 65536
 
@@ -99,7 +99,7 @@ class ImageFile(Image.Image):
         self.decoderconfig = ()
         self.decodermaxblock = MAXBLOCK
 
-        if isPath(fp):
+        if is_path(fp):
             # filename
             self.fp = open(fp, "rb")
             self.filename = fp

src/PIL/ImageFilter.py

@@ -421,8 +421,8 @@ class Color3DLUT(MultibandFilter):
         except TypeError:
             size = (size, size, size)
         size = [int(x) for x in size]
-        for size1D in size:
+        for size_1d in size:
-            if not 2 <= size1D <= 65:
+            if not 2 <= size_1d <= 65:
                 raise ValueError("Size should be in [2, 65] range.")
         return size
 
@@ -439,22 +439,22 @@ class Color3DLUT(MultibandFilter):
         :param target_mode: Passed to the constructor of the resulting
                             lookup table.
         """
-        size1D, size2D, size3D = cls._check_size(size)
+        size_1d, size_2d, size_3d = cls._check_size(size)
         if channels not in (3, 4):
             raise ValueError("Only 3 or 4 output channels are supported")
 
-        table = [0] * (size1D * size2D * size3D * channels)
+        table = [0] * (size_1d * size_2d * size_3d * channels)
         idx_out = 0
-        for b in range(size3D):
+        for b in range(size_3d):
-            for g in range(size2D):
+            for g in range(size_2d):
-                for r in range(size1D):
+                for r in range(size_1d):
                     table[idx_out : idx_out + channels] = callback(
-                        r / (size1D - 1), g / (size2D - 1), b / (size3D - 1)
+                        r / (size_1d - 1), g / (size_2d - 1), b / (size_3d - 1)
                     )
                     idx_out += channels
 
         return cls(
-            (size1D, size2D, size3D),
+            (size_1d, size_2d, size_3d),
             table,
             channels=channels,
             target_mode=target_mode,
@@ -484,20 +484,20 @@ class Color3DLUT(MultibandFilter):
             raise ValueError("Only 3 or 4 output channels are supported")
         ch_in = self.channels
         ch_out = channels or ch_in
-        size1D, size2D, size3D = self.size
+        size_1d, size_2d, size_3d = self.size
 
-        table = [0] * (size1D * size2D * size3D * ch_out)
+        table = [0] * (size_1d * size_2d * size_3d * ch_out)
         idx_in = 0
         idx_out = 0
-        for b in range(size3D):
+        for b in range(size_3d):
-            for g in range(size2D):
+            for g in range(size_2d):
-                for r in range(size1D):
+                for r in range(size_1d):
                     values = self.table[idx_in : idx_in + ch_in]
                     if with_normals:
                         values = callback(
-                            r / (size1D - 1),
+                            r / (size_1d - 1),
-                            g / (size2D - 1),
+                            g / (size_2d - 1),
-                            b / (size3D - 1),
+                            b / (size_3d - 1),
                             *values,
                         )
                     else:

src/PIL/ImageFont.py

@@ -34,7 +34,7 @@ from io import BytesIO
 
 from . import Image
 from ._deprecate import deprecate
-from ._util import isDirectory, isPath
+from ._util import is_directory, is_path
 
 
 class Layout(IntEnum):
@@ -52,7 +52,7 @@ def __getattr__(name):
     raise AttributeError(f"module '{__name__}' has no attribute '{name}'")
 
 
-class _imagingft_not_installed:
+class _ImagingFtNotInstalled:
     # module placeholder
     def __getattr__(self, id):
         raise ImportError("The _imagingft C module is not installed")
@@ -61,7 +61,7 @@ class _imagingft_not_installed:
 try:
     from . import _imagingft as core
 except ImportError:
-    core = _imagingft_not_installed()
+    core = _ImagingFtNotInstalled()
 
 
 # FIXME: add support for pilfont2 format (see FontFile.py)
@@ -198,7 +198,7 @@ class FreeTypeFont:
                 "", size, index, encoding, self.font_bytes, layout_engine
             )
 
-        if isPath(font):
+        if is_path(font):
             if sys.platform == "win32":
                 font_bytes_path = font if isinstance(font, bytes) else font.encode()
                 try:
@@ -863,7 +863,7 @@ def truetype(font=None, size=10, index=0, encoding="", layout_engine=None):
     try:
         return freetype(font)
     except OSError:
-        if not isPath(font):
+        if not is_path(font):
             raise
         ttf_filename = os.path.basename(font)
 
@@ -917,7 +917,7 @@ def load_path(filename):
     :exception OSError: If the file could not be read.
     """
     for directory in sys.path:
-        if isDirectory(directory):
+        if is_directory(directory):
             if not isinstance(filename, str):
                 filename = filename.decode("utf-8")
             try:

src/PIL/ImageQt.py

@@ -20,7 +20,7 @@ import sys
 from io import BytesIO
 
 from . import Image
-from ._util import isPath
+from ._util import is_path
 
 qt_versions = [
     ["6", "PyQt6"],
@@ -140,7 +140,7 @@ def _toqclass_helper(im):
     if hasattr(im, "toUtf8"):
         # FIXME - is this really the best way to do this?
         im = str(im.toUtf8(), "utf-8")
-    if isPath(im):
+    if is_path(im):
         im = Image.open(im)
         exclusive_fp = True
 

src/PIL/ImageStat.py

@@ -78,10 +78,10 @@ class Stat:
 
         v = []
         for i in range(0, len(self.h), 256):
-            layerSum = 0.0
+            layer_sum = 0.0
             for j in range(256):
-                layerSum += j * self.h[i + j]
+                layer_sum += j * self.h[i + j]
-            v.append(layerSum)
+            v.append(layer_sum)
         return v
 
     def _getsum2(self):

src/PIL/PcfFontFile.py

@@ -193,15 +193,15 @@ class PcfFontFile(FontFile.FontFile):
         for i in range(nbitmaps):
             offsets.append(i32(fp.read(4)))
 
-        bitmapSizes = []
+        bitmap_sizes = []
         for i in range(4):
-            bitmapSizes.append(i32(fp.read(4)))
+            bitmap_sizes.append(i32(fp.read(4)))
 
         # byteorder = format & 4  # non-zero => MSB
         bitorder = format & 8  # non-zero => MSB
         padindex = format & 3
 
-        bitmapsize = bitmapSizes[padindex]
+        bitmapsize = bitmap_sizes[padindex]
         offsets.append(bitmapsize)
 
         data = fp.read(bitmapsize)
@@ -225,22 +225,22 @@ class PcfFontFile(FontFile.FontFile):
 
         fp, format, i16, i32 = self._getformat(PCF_BDF_ENCODINGS)
 
-        firstCol, lastCol = i16(fp.read(2)), i16(fp.read(2))
+        first_col, last_col = i16(fp.read(2)), i16(fp.read(2))
-        firstRow, lastRow = i16(fp.read(2)), i16(fp.read(2))
+        first_row, last_row = i16(fp.read(2)), i16(fp.read(2))
 
         i16(fp.read(2))  # default
 
-        nencoding = (lastCol - firstCol + 1) * (lastRow - firstRow + 1)
+        nencoding = (last_col - first_col + 1) * (last_row - first_row + 1)
 
-        encodingOffsets = [i16(fp.read(2)) for _ in range(nencoding)]
+        encoding_offsets = [i16(fp.read(2)) for _ in range(nencoding)]
 
-        for i in range(firstCol, len(encoding)):
+        for i in range(first_col, len(encoding)):
             try:
-                encodingOffset = encodingOffsets[
+                encoding_offset = encoding_offsets[
                     ord(bytearray([i]).decode(self.charset_encoding))
                 ]
-                if encodingOffset != 0xFFFF:
+                if encoding_offset != 0xFFFF:
-                    encoding[i] = encodingOffset
+                    encoding[i] = encoding_offset
             except UnicodeDecodeError:
                 # character is not supported in selected encoding
                 pass

src/PIL/PdfImagePlugin.py

@@ -87,21 +87,21 @@ def _save(im, fp, filename, save_all=False):
         for append_im in append_images:
             append_im.encoderinfo = im.encoderinfo.copy()
             ims.append(append_im)
-    numberOfPages = 0
+    number_of_pages = 0
     image_refs = []
     page_refs = []
     contents_refs = []
     for im in ims:
-        im_numberOfPages = 1
+        im_number_of_pages = 1
         if save_all:
             try:
-                im_numberOfPages = im.n_frames
+                im_number_of_pages = im.n_frames
             except AttributeError:
                 # Image format does not have n_frames.
                 # It is a single frame image
                 pass
-        numberOfPages += im_numberOfPages
+        number_of_pages += im_number_of_pages
-        for i in range(im_numberOfPages):
+        for i in range(im_number_of_pages):
             image_refs.append(existing_pdf.next_object_id(0))
             page_refs.append(existing_pdf.next_object_id(0))
             contents_refs.append(existing_pdf.next_object_id(0))
@@ -111,9 +111,9 @@ def _save(im, fp, filename, save_all=False):
     # catalog and list of pages
     existing_pdf.write_catalog()
 
-    pageNumber = 0
+    page_number = 0
-    for imSequence in ims:
+    for im_sequence in ims:
-        im_pages = ImageSequence.Iterator(imSequence) if save_all else [imSequence]
+        im_pages = ImageSequence.Iterator(im_sequence) if save_all else [im_sequence]
         for im in im_pages:
             # FIXME: Should replace ASCIIHexDecode with RunLengthDecode
             # (packbits) or LZWDecode (tiff/lzw compression).  Note that
@@ -176,7 +176,7 @@ def _save(im, fp, filename, save_all=False):
             width, height = im.size
 
             existing_pdf.write_obj(
-                image_refs[pageNumber],
+                image_refs[page_number],
                 stream=op.getvalue(),
                 Type=PdfParser.PdfName("XObject"),
                 Subtype=PdfParser.PdfName("Image"),
@@ -193,10 +193,10 @@ def _save(im, fp, filename, save_all=False):
             # page
 
             existing_pdf.write_page(
-                page_refs[pageNumber],
+                page_refs[page_number],
                 Resources=PdfParser.PdfDict(
                     ProcSet=[PdfParser.PdfName("PDF"), PdfParser.PdfName(procset)],
-                    XObject=PdfParser.PdfDict(image=image_refs[pageNumber]),
+                    XObject=PdfParser.PdfDict(image=image_refs[page_number]),
                 ),
                 MediaBox=[
                     0,
@@ -204,7 +204,7 @@ def _save(im, fp, filename, save_all=False):
                     width * 72.0 / resolution,
                     height * 72.0 / resolution,
                 ],
-                Contents=contents_refs[pageNumber],
+                Contents=contents_refs[page_number],
             )
 
             #
@@ -215,9 +215,9 @@ def _save(im, fp, filename, save_all=False):
                 height * 72.0 / resolution,
             )
 
-            existing_pdf.write_obj(contents_refs[pageNumber], stream=page_contents)
+            existing_pdf.write_obj(contents_refs[page_number], stream=page_contents)
 
-            pageNumber += 1
+            page_number += 1
 
     #
     # trailer

src/PIL/PyAccess.py

@@ -39,9 +39,9 @@ try:
 except ImportError as ex:
     # Allow error import for doc purposes, but error out when accessing
     # anything in core.
-    from ._util import deferred_error
+    from ._util import DeferredError
 
-    FFI = ffi = deferred_error(ex)
+    FFI = ffi = DeferredError(ex)
 
 logger = logging.getLogger(__name__)
 

src/PIL/SgiImagePlugin.py

@@ -138,7 +138,7 @@ def _save(im, fp, filename):
     # Flip the image, since the origin of SGI file is the bottom-left corner
     orientation = -1
     # Define the file as SGI File Format
-    magicNumber = 474
+    magic_number = 474
     # Run-Length Encoding Compression - Unsupported at this time
     rle = 0
 
@@ -167,11 +167,11 @@ def _save(im, fp, filename):
     # Maximum Byte value (255 = 8bits per pixel)
     pinmax = 255
     # Image name (79 characters max, truncated below in write)
-    imgName = os.path.splitext(os.path.basename(filename))[0]
+    img_name = os.path.splitext(os.path.basename(filename))[0]
-    imgName = imgName.encode("ascii", "ignore")
+    img_name = img_name.encode("ascii", "ignore")
     # Standard representation of pixel in the file
     colormap = 0
-    fp.write(struct.pack(">h", magicNumber))
+    fp.write(struct.pack(">h", magic_number))
     fp.write(o8(rle))
     fp.write(o8(bpc))
     fp.write(struct.pack(">H", dim))
@@ -181,8 +181,8 @@ def _save(im, fp, filename):
     fp.write(struct.pack(">l", pinmin))
     fp.write(struct.pack(">l", pinmax))
     fp.write(struct.pack("4s", b""))  # dummy
-    fp.write(struct.pack("79s", imgName))  # truncates to 79 chars
+    fp.write(struct.pack("79s", img_name))  # truncates to 79 chars
-    fp.write(struct.pack("s", b""))  # force null byte after imgname
+    fp.write(struct.pack("s", b""))  # force null byte after img_name
     fp.write(struct.pack(">l", colormap))
     fp.write(struct.pack("404s", b""))  # dummy
 

src/PIL/TiffImagePlugin.py

@@ -1336,14 +1336,14 @@ class TiffImageFile(ImageFile.ImageFile):
 
         logger.debug(f"- size: {self.size}")
 
-        sampleFormat = self.tag_v2.get(SAMPLEFORMAT, (1,))
+        sample_format = self.tag_v2.get(SAMPLEFORMAT, (1,))
-        if len(sampleFormat) > 1 and max(sampleFormat) == min(sampleFormat) == 1:
+        if len(sample_format) > 1 and max(sample_format) == min(sample_format) == 1:
             # SAMPLEFORMAT is properly per band, so an RGB image will
             # be (1,1,1).  But, we don't support per band pixel types,
             # and anything more than one band is a uint8. So, just
             # take the first element. Revisit this if adding support
             # for more exotic images.
-            sampleFormat = (1,)
+            sample_format = (1,)
 
         bps_tuple = self.tag_v2.get(BITSPERSAMPLE, (1,))
         extra_tuple = self.tag_v2.get(EXTRASAMPLES, ())
@@ -1364,18 +1364,18 @@ class TiffImageFile(ImageFile.ImageFile):
             # presume it is the same number of bits for all of the samples.
             bps_tuple = bps_tuple * bps_count
 
-        samplesPerPixel = self.tag_v2.get(
+        samples_per_pixel = self.tag_v2.get(
             SAMPLESPERPIXEL,
             3 if self._compression == "tiff_jpeg" and photo in (2, 6) else 1,
         )
-        if len(bps_tuple) != samplesPerPixel:
+        if len(bps_tuple) != samples_per_pixel:
             raise SyntaxError("unknown data organization")
 
         # mode: check photometric interpretation and bits per pixel
         key = (
             self.tag_v2.prefix,
             photo,
-            sampleFormat,
+            sample_format,
             fillorder,
             bps_tuple,
             extra_tuple,
@@ -1880,16 +1880,16 @@ class AppendingTiffWriter:
         self.whereToWriteNewIFDOffset = None
         self.offsetOfNewPage = 0
 
-        self.IIMM = IIMM = self.f.read(4)
+        self.IIMM = iimm = self.f.read(4)
-        if not IIMM:
+        if not iimm:
             # empty file - first page
             self.isFirst = True
             return
 
         self.isFirst = False
-        if IIMM == b"II\x2a\x00":
+        if iimm == b"II\x2a\x00":
             self.setEndian("<")
-        elif IIMM == b"MM\x00\x2a":
+        elif iimm == b"MM\x00\x2a":
             self.setEndian(">")
         else:
             raise RuntimeError("Invalid TIFF file header")
@@ -1904,20 +1904,20 @@ class AppendingTiffWriter:
         # fix offsets
         self.f.seek(self.offsetOfNewPage)
 
-        IIMM = self.f.read(4)
+        iimm = self.f.read(4)
-        if not IIMM:
+        if not iimm:
             # raise RuntimeError("nothing written into new page")
             # Make it easy to finish a frame without committing to a new one.
             return
 
-        if IIMM != self.IIMM:
+        if iimm != self.IIMM:
             raise RuntimeError("IIMM of new page doesn't match IIMM of first page")
 
-        IFDoffset = self.readLong()
+        ifd_offset = self.readLong()
-        IFDoffset += self.offsetOfNewPage
+        ifd_offset += self.offsetOfNewPage
         self.f.seek(self.whereToWriteNewIFDOffset)
-        self.writeLong(IFDoffset)
+        self.writeLong(ifd_offset)
-        self.f.seek(IFDoffset)
+        self.f.seek(ifd_offset)
         self.fixIFD()
 
     def newFrame(self):
@@ -1948,9 +1948,9 @@ class AppendingTiffWriter:
         pos = self.f.tell()
 
         # pad to 16 byte boundary
-        padBytes = 16 - pos % 16
+        pad_bytes = 16 - pos % 16
-        if 0 < padBytes < 16:
+        if 0 < pad_bytes < 16:
-            self.f.write(bytes(padBytes))
+            self.f.write(bytes(pad_bytes))
         self.offsetOfNewPage = self.f.tell()
 
     def setEndian(self, endian):
@@ -1961,14 +1961,14 @@ class AppendingTiffWriter:
 
     def skipIFDs(self):
         while True:
-            IFDoffset = self.readLong()
+            ifd_offset = self.readLong()
-            if IFDoffset == 0:
+            if ifd_offset == 0:
                 self.whereToWriteNewIFDOffset = self.f.tell() - 4
                 break
 
-            self.f.seek(IFDoffset)
+            self.f.seek(ifd_offset)
-            numTags = self.readShort()
+            num_tags = self.readShort()
-            self.f.seek(numTags * 12, os.SEEK_CUR)
+            self.f.seek(num_tags * 12, os.SEEK_CUR)
 
     def write(self, data):
         return self.f.write(data)
@@ -1983,68 +1983,68 @@ class AppendingTiffWriter:
 
     def rewriteLastShortToLong(self, value):
         self.f.seek(-2, os.SEEK_CUR)
-        bytesWritten = self.f.write(struct.pack(self.longFmt, value))
+        bytes_written = self.f.write(struct.pack(self.longFmt, value))
-        if bytesWritten is not None and bytesWritten != 4:
+        if bytes_written is not None and bytes_written != 4:
-            raise RuntimeError(f"wrote only {bytesWritten} bytes but wanted 4")
+            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 4")
 
     def rewriteLastShort(self, value):
         self.f.seek(-2, os.SEEK_CUR)
-        bytesWritten = self.f.write(struct.pack(self.shortFmt, value))
+        bytes_written = self.f.write(struct.pack(self.shortFmt, value))
-        if bytesWritten is not None and bytesWritten != 2:
+        if bytes_written is not None and bytes_written != 2:
-            raise RuntimeError(f"wrote only {bytesWritten} bytes but wanted 2")
+            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 2")
 
     def rewriteLastLong(self, value):
         self.f.seek(-4, os.SEEK_CUR)
-        bytesWritten = self.f.write(struct.pack(self.longFmt, value))
+        bytes_written = self.f.write(struct.pack(self.longFmt, value))
-        if bytesWritten is not None and bytesWritten != 4:
+        if bytes_written is not None and bytes_written != 4:
-            raise RuntimeError(f"wrote only {bytesWritten} bytes but wanted 4")
+            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 4")
 
     def writeShort(self, value):
-        bytesWritten = self.f.write(struct.pack(self.shortFmt, value))
+        bytes_written = self.f.write(struct.pack(self.shortFmt, value))
-        if bytesWritten is not None and bytesWritten != 2:
+        if bytes_written is not None and bytes_written != 2:
-            raise RuntimeError(f"wrote only {bytesWritten} bytes but wanted 2")
+            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 2")
 
     def writeLong(self, value):
-        bytesWritten = self.f.write(struct.pack(self.longFmt, value))
+        bytes_written = self.f.write(struct.pack(self.longFmt, value))
-        if bytesWritten is not None and bytesWritten != 4:
+        if bytes_written is not None and bytes_written != 4:
-            raise RuntimeError(f"wrote only {bytesWritten} bytes but wanted 4")
+            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 4")
 
     def close(self):
         self.finalize()
         self.f.close()
 
     def fixIFD(self):
-        numTags = self.readShort()
+        num_tags = self.readShort()
 
-        for i in range(numTags):
+        for i in range(num_tags):
-            tag, fieldType, count = struct.unpack(self.tagFormat, self.f.read(8))
+            tag, field_type, count = struct.unpack(self.tagFormat, self.f.read(8))
 
-            fieldSize = self.fieldSizes[fieldType]
+            field_size = self.fieldSizes[field_type]
-            totalSize = fieldSize * count
+            total_size = field_size * count
-            isLocal = totalSize <= 4
+            is_local = total_size <= 4
-            if not isLocal:
+            if not is_local:
                 offset = self.readLong()
                 offset += self.offsetOfNewPage
                 self.rewriteLastLong(offset)
 
             if tag in self.Tags:
-                curPos = self.f.tell()
+                cur_pos = self.f.tell()
 
-                if isLocal:
+                if is_local:
                     self.fixOffsets(
-                        count, isShort=(fieldSize == 2), isLong=(fieldSize == 4)
+                        count, isShort=(field_size == 2), isLong=(field_size == 4)
                     )
-                    self.f.seek(curPos + 4)
+                    self.f.seek(cur_pos + 4)
                 else:
                     self.f.seek(offset)
                     self.fixOffsets(
-                        count, isShort=(fieldSize == 2), isLong=(fieldSize == 4)
+                        count, isShort=(field_size == 2), isLong=(field_size == 4)
                     )
-                    self.f.seek(curPos)
+                    self.f.seek(cur_pos)
 
-                offset = curPos = None
+                offset = cur_pos = None
 
-            elif isLocal:
+            elif is_local:
                 # skip the locally stored value that is not an offset
                 self.f.seek(4, os.SEEK_CUR)
 

src/PIL/_util.py

@@ -2,16 +2,16 @@ import os
 from pathlib import Path
 
 
-def isPath(f):
+def is_path(f):
     return isinstance(f, (bytes, str, Path))
 
 
-# Checks if an object is a string, and that it points to a directory.
+def is_directory(f):
-def isDirectory(f):
+    """Checks if an object is a string, and that it points to a directory."""
-    return isPath(f) and os.path.isdir(f)
+    return is_path(f) and os.path.isdir(f)
 
 
-class deferred_error:
+class DeferredError:
     def __init__(self, ex):
         self.ex = ex