reapply the _fields check, it's needed for CPython 2.5
reapply the _fields check, it's needed for CPython 2.5

git-svn-id: c218ddd0ead49d0ebd0ba300e318fe350cc5c9d4@430 77be9137-0722-0410-abbc-c588f5bf0654

kindy61/mako,bdoms/mako