Removed Undefined var duplication

Author: syrusakbary

graphql/type/definition.py

@@ -5,6 +5,7 @@
 from ..pyutils.cached_property import cached_property
 from ..pyutils.ordereddict import OrderedDict
 from ..utils.assert_valid_name import assert_valid_name
+from ..utils.undefined import Undefined
 
 
 def is_type(type):
@@ -478,11 +479,6 @@ def define_enum_values(type, value_map):
     return values
 
 
-class Undefined(object):
-    """A representation of an Undefined value distinct from a None value"""
-    pass
-
-
 class GraphQLEnumValue(object):
     __slots__ = 'name', 'value', 'deprecation_reason', 'description'
 

graphql/utils/undefined.py

@@ -1,4 +1,6 @@
 class _Undefined(object):
+    """A representation of an Undefined value distinct from a None value"""
+
     def __bool__(self):
         return False