fix add_metaclass when __slots__ is a string (fixes #47)

1 files changed, 6 insertions, 2 deletions

diff --git a/six.py b/six.py
index f782f9a..a0eea9a 100644
--- a/six.py
+++ b/six.py
@@ -581,7 +581,11 @@ def add_metaclass(metaclass):
         orig_vars = cls.__dict__.copy()
         orig_vars.pop('__dict__', None)
         orig_vars.pop('__weakref__', None)
-        for slots_var in orig_vars.get('__slots__', ()):
-            orig_vars.pop(slots_var)
+        slots = orig_vars.get('__slots__')
+        if slots is not None:
+            if isinstance(slots, str):
+                slots = [slots]
+            for slots_var in slots:
+                orig_vars.pop(slots_var)
         return metaclass(cls.__name__, cls.__bases__, orig_vars)
     return wrapper