minor: Add noqa and remove unused property

Author: abawchen

graphene_mongo/fields.py

@@ -92,10 +92,6 @@ def get_reference_field(r, kv):
             return r
         return reduce(get_reference_field, self.fields.items(), {})
 
-    @property
-    def filter_fields(self):
-        return self._type._meta.filter_fields
-
     @property
     def fields(self):
         return self._type._meta.fields

graphene_mongo/types.py

@@ -117,6 +117,7 @@ def __init_subclass_with_meta__(cls, model=None, registry=None, skip_registry=Fa
                 cls._meta.fields.update(mongoengine_fields)
                 registry.register(cls)
 
+    # noqa
     @classmethod
     def is_type_of(cls, root, info):
         if isinstance(root, cls):