Removed unnecessary empty parentheses in class definitions.

tests/model_fields/tests.py

@@ -9,7 +9,7 @@ from .models import (
 )
 
 
-class Nested():
+class Nested:
     class Field(models.Field):
         pass
 

tests/pagination/tests.py

@@ -339,7 +339,7 @@ class ModelPaginationTests(TestCase):
         Unordered object list warning with an object that has an orderd
         attribute but not a model attribute.
         """
-        class ObjectList():
+        class ObjectList:
             ordered = False
         object_list = ObjectList()
         with warnings.catch_warnings(record=True) as warns: