--- enum.py	2019-12-04 09:00:51.102002690 +0000
+++ enum_new.py	2019-12-04 09:02:31.011340858 +0000
@@ -58,7 +58,7 @@
 
         """
         if _is_sunder(key):
-            raise ValueError('_names_ are reserved for future Enum use')
+            raise ValueError('Names surrounded by underscore (such as "%s") are reserved for future Enum use' % key)
         elif _is_dunder(key):
             pass
         elif key in self._member_names: