1 files changed, 3 insertions, 1 deletions
diff --git a/Lib/enum.py b/Lib/enum.py
index 1efddfa..7ad599b 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -430,7 +430,9 @@ class _EnumDict(dict):
             if isinstance(value, auto):
                 single = True
                 value = (value, )
-            if isinstance(value, tuple):
+            if type(value) is tuple and any(isinstance(v, auto) for v in value):
+                # insist on an actual tuple, no subclasses, in keeping with only supporting
+                # top-level auto() usage (not contained in any other data structure)
                 auto_valued = []
                 for v in value:
                     if isinstance(v, auto):