diff --git a/enum_new.py b/replacement_new.py
index 81a042b..321cd8a 100644
--- a/enum_new.py
+++ b/replacement_new.py
@@ -1,5 +1,12 @@
 
-    def __new__(cls, value):
+def _replacement__new__(cls, value):
+	""" Copied from python standard library enum.py class Enum.
+	Prevent cyclic references on ValueError during construction.
+	Local variable exc must be deleted, otherwise:
+	- ref to exc held by the frame
+	- ref to traceback held by exc
+	- ref to frame held by traceback
+	"""
 	# all enum instances are actually created during class construction
 	# without calling this method; this method is called by the metaclass'
 	# __call__ (i.e. Color(3) ), and by pickle
@@ -20,21 +27,23 @@
 				return member
 	# still not found -- try _missing_ hook
 	try:
-            exc = None
 		result = cls._missing_(value)
 	except Exception as e:
-            exc = e
-            result = None
+		e.__context__ = ValueError("%r is not a valid %s" % (value, cls.__name__))
+		raise e
+
 	if isinstance(result, cls):
 		return result
-        else:
-            ve_exc = ValueError("%r is not a valid %s" % (value, cls.__name__))
-            if result is None and exc is None:
+
+	with ValueError(
+		"%r is not a valid %s" % (value, cls.__name__)
+	) as ve_exc:
+		if result is None:
 			raise ve_exc
-            elif exc is None:
-                exc = TypeError(
+
+		te_exc = TypeError(
 			'error in %s._missing_: returned %r instead of None or a valid member'
 			% (cls.__name__, result)
 		)
-            exc.__context__ = ve_exc
-            raise exc
+		te_exc.__context__ = ve_exc
+		raise te_exc