diff --git a/graphene_django/registry.py b/graphene_django/registry.py
index 5a7b2af..2c0702c 100644
--- a/graphene_django/registry.py
+++ b/graphene_django/registry.py
@@ -25,8 +25,11 @@ class Registry(object):
         return self._registry.get(model)
 
     def get_model_by_string(self, model):
+        print(self.__dict__)
+        print(self._registry.__dict__)
+        print(self._field_registry)
         print(self._registry.keys())
-        return filter(lambda x: model == x.__name__, self._registry.keys())[0]
+        return list(filter(lambda x: model == x.__name__, self._registry.keys()))[0]
 
 
     def register_converted_field(self, field, converted):