Remove unnecessary Python version compatibility bits

Author: akx

polymorphic/base.py

@@ -52,8 +52,6 @@ class PolymorphicModelBase(ModelBase):
     """
 
     def __new__(self, model_name, bases, attrs, **kwargs):
-        # print; print '###', model_name, '- bases:', bases
-
         # Workaround compatibility issue with six.with_metaclass() and custom Django model metaclasses:
         if not attrs and model_name == "NewBase":
             return super().__new__(self, model_name, bases, attrs, **kwargs)

polymorphic/compat.py

@@ -6,8 +6,6 @@
 from django.db.models.fields.related import ForwardManyToOneDescriptor, ReverseOneToOneDescriptor
 from django.db.utils import DEFAULT_DB_ALIAS
 
-from polymorphic.compat import with_metaclass
-
 from .base import PolymorphicModelBase
 from .managers import PolymorphicManager
 from .query_translate import translate_polymorphic_Q_object
@@ -24,7 +22,7 @@ class PolymorphicTypeInvalid(RuntimeError):
     pass
 
 
-class PolymorphicModel(with_metaclass(PolymorphicModelBase, models.Model)):
+class PolymorphicModel(models.Model, metaclass=PolymorphicModelBase):
     """
     Abstract base class that provides polymorphic behaviour
     for any model directly or indirectly derived from it.

polymorphic/models.py

@@ -38,7 +38,7 @@ def translate_polymorphic_filter_definitions_in_kwargs(
     Returns: a list of non-keyword-arguments (Q objects) to be added to the filter() query.
     """
     additional_args = []
-    for field_path, val in kwargs.copy().items():  # Python 3 needs copy
+    for field_path, val in kwargs.copy().items():  # `copy` so we're not mutating the dict
         new_expr = _translate_polymorphic_filter_definition(
             queryset_model, field_path, val, using=using
         )

polymorphic/query_translate.py

@@ -8,7 +8,7 @@
 from django.db.utils import IntegrityError
 from django.test import TransactionTestCase
 
-from polymorphic import compat, query_translate
+from polymorphic import query_translate
 from polymorphic.managers import PolymorphicManager
 from polymorphic.models import PolymorphicTypeInvalid, PolymorphicTypeUndefined
 from polymorphic.tests.models import (