diff -r 37505d64e57b -r f2e327a7c5de thirdparty/google_appengine/google/appengine/ext/db/__init__.py
--- a/thirdparty/google_appengine/google/appengine/ext/db/__init__.py	Tue Sep 16 01:18:49 2008 +0000
+++ b/thirdparty/google_appengine/google/appengine/ext/db/__init__.py	Tue Sep 16 02:28:33 2008 +0000
@@ -2129,6 +2129,8 @@
 
     Note that the only permissible value for 'required' is True.
     """
+    if item_type is str:
+      item_type = basestring
     if not isinstance(item_type, type):
       raise TypeError('Item type should be a type object')
     if item_type not in _ALLOWED_PROPERTY_TYPES: