The built-ins 'dict' and 'list' are not what they supposed to be in a Python environment: print isinstance('foo', dict) return printed will raise a TypeError because 'dict' represents an instance of ZopeGuards.GuardedDictType. This behaviour is confusing if you are not aware of it. At least the documentation of PythonScripts should be updated to reflect the differences. -aj -- Andreas Jung -------------------------------- www.zopyx.com Software-Entwicklung und Consulting Andreas Jung