various fixes

mypy_django_plugin/transformers/models.py

@@ -1,6 +1,5 @@
 from abc import ABCMeta, abstractmethod
-from abc import ABCMeta, abstractmethod
-from typing import cast, Type
+from typing import Type, cast
 
 from django.db.models.base import Model
 from django.db.models.fields.related import ForeignKey
@@ -18,7 +17,7 @@ from mypy_django_plugin.transformers import fields
 from mypy_django_plugin.transformers.fields import get_field_descriptor_types
 
 
-class ModelClassInitializer(metaclass=ABCMeta):
+class ModelClassInitializer:
     def __init__(self, ctx: ClassDefContext, django_context: DjangoContext):
         self.api = cast(NewSemanticAnalyzer, ctx.api)
         self.model_classdef = ctx.cls
@@ -52,7 +51,6 @@ class ModelClassInitializer(metaclass=ABCMeta):
             return
         self.run_with_model_cls(model_cls)
 
-    @abstractmethod
     def run_with_model_cls(self, model_cls):
         pass
 
@@ -70,7 +68,7 @@ class InjectAnyAsBaseForNestedMeta(ModelClassInitializer):
     to get around incompatible Meta inner classes for different models.
     """
 
-    def run_with_model_cls(self, model_cls: Type[Model])-> None:
+    def run(self) -> None:
         meta_node = helpers.get_nested_meta_node_for_current_class(self.model_classdef.info)
         if meta_node is None:
             return None
@@ -78,7 +76,7 @@ class InjectAnyAsBaseForNestedMeta(ModelClassInitializer):
 
 
 class AddDefaultPrimaryKey(ModelClassInitializer):
-    def run_with_model_cls(self, model_cls: Type[Model])-> None:
+    def run_with_model_cls(self, model_cls: Type[Model]) -> None:
         auto_field = model_cls._meta.auto_field
         if auto_field and not self.model_classdef.info.has_readable_member(auto_field.attname):
             # autogenerated field
@@ -91,7 +89,7 @@ class AddDefaultPrimaryKey(ModelClassInitializer):
 
 
 class AddRelatedModelsId(ModelClassInitializer):
-    def run_with_model_cls(self, model_cls: Type[Model])-> None:
+    def run_with_model_cls(self, model_cls: Type[Model]) -> None:
         for field in model_cls._meta.get_fields():
             if isinstance(field, ForeignKey):
                 rel_primary_key_field = self.django_context.get_primary_key_field(field.related_model)
@@ -103,7 +101,7 @@ class AddRelatedModelsId(ModelClassInitializer):
 
 
 class AddManagers(ModelClassInitializer):
-    def run_with_model_cls(self, model_cls: Type[Model])-> None:
+    def run_with_model_cls(self, model_cls: Type[Model]) -> None:
         for manager_name, manager in model_cls._meta.managers_map.items():
             if manager_name not in self.model_classdef.info.names:
                 manager_fullname = helpers.get_class_fullname(manager.__class__)
@@ -140,7 +138,7 @@ class AddManagers(ModelClassInitializer):
 
 
 class AddExtraFieldMethods(ModelClassInitializer):
-    def run_with_model_cls(self, model_cls: Type[Model])-> None:
+    def run_with_model_cls(self, model_cls: Type[Model]) -> None:
         # get_FOO_display for choices
         for field in self.django_context.get_model_fields(model_cls):
             if field.choices:
@@ -172,7 +170,7 @@ class AddExtraFieldMethods(ModelClassInitializer):
 
 
 class AddMetaOptionsAttribute(ModelClassInitializer):
-    def run_with_model_cls(self, model_cls: Type[Model])-> None:
+    def run_with_model_cls(self, model_cls: Type[Model]) -> None:
         if '_meta' not in self.model_classdef.info.names:
             options_info = self.lookup_typeinfo_or_incomplete_defn_error(fullnames.OPTIONS_CLASS_FULLNAME)
             self.add_new_node_to_model_class('_meta',