XMP feature added

Tests/test_image_getxmp.py

@@ -2,7 +2,8 @@ from PIL import Image
 
 
 def test_getxmp():
-    im = Image.open("Tests/images/hopper.jpg")
+    im = Image.open("Tests/images/xmp_test.jpg")
     type_repr = repr(type(im.getxmp()))
 
     assert "dict" in type_repr
+    assert isinstance(im.getxmp()['Description'][0]['Version'], int)

src/PIL/Image.py

@@ -1324,8 +1324,10 @@ class Image:
         Returns an object containing the xmp tags for a given image.
         :returns: XMP tags in an object.
         """
+
         if self._xmp is None:
             self._xmp = {}
+            
         for segment, content in self.applist:
             if segment == "APP1":
                 marker, xmp_tags = content.rsplit(b"\x00", 1)