remove more python2 compat codes

rest_framework/compat.py

@@ -10,12 +10,7 @@ from django.core import validators
 from django.utils import six
 from django.views.generic import View
 
-try:
+from collections.abc import Mapping, MutableMapping   # noqa
-    # Python 3
-    from collections.abc import Mapping, MutableMapping   # noqa
-except ImportError:
-    # Python 2.7
-    from collections import Mapping, MutableMapping   # noqa
 
 try:
     from django.urls import (  # noqa
@@ -292,7 +287,7 @@ else:
     INDENT_SEPARATORS = (b',', b': ')
 
 
-class CustomValidatorMessage(object):
+class CustomValidatorMessage:
     """
     We need to avoid evaluation of `lazy` translated `message` in `django.core.validators.BaseValidator.__init__`.
     https://github.com/django/django/blob/75ed5900321d170debef4ac452b8b3cf8a1c2384/django/core/validators.py#L297
@@ -302,7 +297,7 @@ class CustomValidatorMessage(object):
 
     def __init__(self, *args, **kwargs):
         self.message = kwargs.pop('message', self.message)
-        super(CustomValidatorMessage, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
 
 
 class MinValueValidator(CustomValidatorMessage, validators.MinValueValidator):

rest_framework/fields.py

@@ -183,18 +183,18 @@ def iter_options(grouped_choices, cutoff=None, cutoff_text=None):
     """
     Helper function for options and option groups in templates.
     """
-    class StartOptionGroup(object):
+    class StartOptionGroup:
         start_option_group = True
         end_option_group = False
 
         def __init__(self, label):
             self.label = label
 
-    class EndOptionGroup(object):
+    class EndOptionGroup:
         start_option_group = False
         end_option_group = True
 
-    class Option(object):
+    class Option:
         start_option_group = False
         end_option_group = False
 
@@ -249,7 +249,7 @@ def get_error_detail(exc_info):
     }
 
 
-class CreateOnlyDefault(object):
+class CreateOnlyDefault:
     """
     This class may be used to provide default values that are only used
     for create operations, but that do not return any value for update
@@ -276,7 +276,7 @@ class CreateOnlyDefault(object):
         )
 
 
-class CurrentUserDefault(object):
+class CurrentUserDefault:
     def set_context(self, serializer_field):
         self.user = serializer_field.context['request'].user
 
@@ -303,7 +303,7 @@ MISSING_ERROR_MESSAGE = (
 )
 
 
-class Field(object):
+class Field:
     _creation_counter = 0
 
     default_error_messages = {

rest_framework/relations.py

@@ -65,7 +65,7 @@ class Hyperlink(six.text_type):
     is_hyperlink = True
 
 
-class PKOnlyObject(object):
+class PKOnlyObject:
     """
     This is a mock object, used for when we only need the pk of the object
     instance, but still want to return an object with a .pk attribute,

rest_framework/renderers.py

@@ -39,7 +39,7 @@ def zero_as_none(value):
     return None if value == 0 else value
 
 
-class BaseRenderer(object):
+class BaseRenderer:
     """
     All renderers should extend this class, setting the `media_type`
     and `format` attributes, and override the `.render()` method.

rest_framework/routers.py

@@ -38,7 +38,7 @@ Route = namedtuple('Route', ['url', 'mapping', 'name', 'detail', 'initkwargs'])
 DynamicRoute = namedtuple('DynamicRoute', ['url', 'name', 'detail', 'initkwargs'])
 
 
-class DynamicDetailRoute(object):
+class DynamicDetailRoute:
     def __new__(cls, url, name, initkwargs):
         warnings.warn(
             "`DynamicDetailRoute` is deprecated and will be removed in 3.10 "
@@ -49,7 +49,7 @@ class DynamicDetailRoute(object):
         return DynamicRoute(url, name, True, initkwargs)
 
 
-class DynamicListRoute(object):
+class DynamicListRoute:
     def __new__(cls, url, name, initkwargs):
         warnings.warn(
             "`DynamicListRoute` is deprecated and will be removed in 3.10 in "

rest_framework/settings.py

@@ -186,7 +186,7 @@ def import_from_string(val, setting_name):
         raise ImportError(msg)
 
 
-class APISettings(object):
+class APISettings:
     """
     A settings object, that allows API settings to be accessed as properties.
     For example:

rest_framework/test.py

@@ -30,7 +30,7 @@ if requests is not None:
         def get_all(self, key, default):
             return self.getheaders(key)
 
-    class MockOriginalResponse(object):
+    class MockOriginalResponse:
         def __init__(self, headers):
             self.msg = HeaderDict(headers)
             self.closed = False

rest_framework/throttling.py

@@ -10,7 +10,7 @@ from django.core.exceptions import ImproperlyConfigured
 from rest_framework.settings import api_settings
 
 
-class BaseThrottle(object):
+class BaseThrottle:
     """
     Rate throttling of requests.
     """

rest_framework/validators.py

@@ -32,7 +32,7 @@ def qs_filter(queryset, **kwargs):
         return queryset.none()
 
 
-class UniqueValidator(object):
+class UniqueValidator:
     """
     Validator that corresponds to `unique=True` on a model field.
 
@@ -87,7 +87,7 @@ class UniqueValidator(object):
         ))
 
 
-class UniqueTogetherValidator(object):
+class UniqueTogetherValidator:
     """
     Validator that corresponds to `unique_together = (...)` on a model class.
 
@@ -176,7 +176,7 @@ class UniqueTogetherValidator(object):
         ))
 
 
-class BaseUniqueForValidator(object):
+class BaseUniqueForValidator:
     message = None
     missing_message = _('This field is required.')
 

rest_framework/versioning.py

@@ -10,7 +10,7 @@ from rest_framework.templatetags.rest_framework import replace_query_param
 from rest_framework.utils.mediatypes import _MediaType
 
 
-class BaseVersioning(object):
+class BaseVersioning:
     default_version = api_settings.DEFAULT_VERSION
     allowed_versions = api_settings.ALLOWED_VERSIONS
     version_param = api_settings.VERSION_PARAM

rest_framework/viewsets.py

@@ -33,7 +33,7 @@ def _is_extra_action(attr):
     return hasattr(attr, 'mapping')
 
 
-class ViewSetMixin(object):
+class ViewSetMixin:
     """
     This is the magic.
 

tests/authentication/migrations/0001_initial.py

@@ -1,6 +1,3 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
 from django.conf import settings
 from django.db import migrations, models
 

tests/authentication/models.py

@@ -1,6 +1,3 @@
-# coding: utf-8
-from __future__ import unicode_literals
-
 from django.conf import settings
 from django.db import models
 

tests/authentication/test_authentication.py

@@ -249,7 +249,7 @@ class SessionAuthTests(TestCase):
         assert response.status_code == status.HTTP_403_FORBIDDEN
 
 
-class BaseTokenAuthTests(object):
+class BaseTokenAuthTests:
     """Token authentication"""
     model = None
     path = None

tests/generic_relations/models.py

@@ -5,10 +5,8 @@ from django.contrib.contenttypes.fields import (
 )
 from django.contrib.contenttypes.models import ContentType
 from django.db import models
-from django.utils.encoding import python_2_unicode_compatible
 
 
-@python_2_unicode_compatible
 class Tag(models.Model):
     """
     Tags have a descriptive slug, and are attached to an arbitrary object.
@@ -22,7 +20,6 @@ class Tag(models.Model):
         return self.tag
 
 
-@python_2_unicode_compatible
 class Bookmark(models.Model):
     """
     A URL bookmark that may have multiple tags attached.
@@ -34,7 +31,6 @@ class Bookmark(models.Model):
         return 'Bookmark: %s' % self.url
 
 
-@python_2_unicode_compatible
 class Note(models.Model):
     """
     A textual note that may have multiple tags attached.