Revert r42719, because the isinstance() check wasn't redundant; formatting a
string exception was causing a TypeError.
diff --git a/Lib/traceback.py b/Lib/traceback.py
index 4971906..d4a4011 100644
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -158,7 +158,7 @@
     """
     list = []
     if (type(etype) == types.ClassType
-        or issubclass(etype, Exception)):
+        or (isinstance(etype, type) and issubclass(etype, Exception))):
         stype = etype.__name__
     else:
         stype = etype