So I've run into a minor TAL problem recently. I'm trying to test to see if an object is a List or a Tuple (or more generally a sequence that isn't a string), but can't figure out a way. I've tried the following: python:isinstance(obj, list) doesn't work (it doesn't recoginze 'list' as a 'class, type or tuple of classes and types'), strangely: python:isinstance(obj, str) works ('str' is ok, but not 'list' or 'tuple'?). Also: python:list(obj) works despite the fact that 'list' is not recognized as a class! using: python:type(obj) is type([]) fails because type() is not recognized in TAL. using: python:hasattr(obj, '__iter__') fails also, though I'm not sure why (probably TAL doesn't bother with variables starting with '_'). And it's impossible to pull 'ListType' etc. in using modules['types'], because of the lack of security assertions on the 'types' module. There must be a way to do a simple type check for a tuple without a python script, no? Right now I'm using: tal:define="dictish nocall:obj/keys|nothing; listish python:not dictish and len(obj) and (len(obj[0]) != 1)" Which is far too kludgy, brittle, and plain incorrect for my liking. Thanks, Alec Mitchell