Fix duplicated ErrorType declaration

graphene_django/forms/mutation.py

@@ -14,7 +14,7 @@ from graphene.types.utils import yank_fields_from_attrs
 from graphene_django.registry import get_global_registry
 
 from .converter import convert_form_field
-from .types import ErrorType
+from ..types import ErrorType
 
 
 def fields_for_form(form, only_fields, exclude_fields):

graphene_django/rest_framework/mutation.py

@@ -9,7 +9,7 @@ from graphene.relay.mutation import ClientIDMutation
 from graphene.types.objecttype import yank_fields_from_attrs
 
 from .serializer_converter import convert_serializer_field
-from .types import ErrorType
+from ..types import ErrorType
 
 
 class SerializerMutationOptions(MutationOptions):

graphene_django/rest_framework/types.py

@@ -2,11 +2,6 @@ import graphene
 from graphene.types.unmountedtype import UnmountedType
 
 
-class ErrorType(graphene.ObjectType):
-    field = graphene.String(required=True)
-    messages = graphene.List(graphene.NonNull(graphene.String), required=True)
-
-
 class DictType(UnmountedType):
     key = graphene.String()
     value = graphene.String()

graphene_django/types.py

@@ -1,6 +1,7 @@
 from collections import OrderedDict
 
 from django.utils.functional import SimpleLazyObject
+import graphene
 from graphene import Field
 from graphene.relay import Connection, Node
 from graphene.types.objecttype import ObjectType, ObjectTypeOptions
@@ -133,3 +134,8 @@ class DjangoObjectType(ObjectType):
             return cls._meta.model.objects.get(pk=id)
         except cls._meta.model.DoesNotExist:
             return None
+
+
+class ErrorType(ObjectType):
+    field = graphene.String(required=True)
+    messages = graphene.List(graphene.NonNull(graphene.String), required=True)