Index: Lib/collections.py
===================================================================
--- Lib/collections.py	(revision 55472)
+++ Lib/collections.py	(working copy)
@@ -20,11 +20,15 @@
     33
     >>> p                       # readable __repr__ with name=value style
     Point(x=11, y=22)
-
     """
-
+    # protect against exec attacks
+    if not typename.replace('_', '').isalnum():
+        raise ValueError("typename '%s' contains invalid characters." %
+	                 typename)
+    if not ''.join(field_names).replace('_', '').isalnum():
+        raise ValueError("field_names '%s' contains invalid characters." %
+	                 typename)
     field_names = s.split()
-    assert ''.join(field_names).replace('_', '').isalpha()      # protect against exec attacks
     argtxt = ', '.join(field_names)
     reprtxt = ', '.join('%s=%%r' % name for name in field_names)
     template = '''class %(typename)s(tuple):