Mark Dickinson added the comment: Nick Coghlan pointed out that a lot of this discussion has already happened for the function signature object PEP [1]. That PEP defines constants Parameter.POSITIONAL_ONLY Parameter.POSITIONAL_OR_KEYWORD Parameter.KEYWORD_ONLY Parameter.VAR_POSITIONAL Parameter.VAR_KEYWORD So the 'positional' in the TypeError messages corresponds to POSITIONAL_OR_KEYWORD. [1] http://www.python.org/dev/peps/pep-0362/ ---------- _______________________________________ Python tracker <report at bugs.python.org> <http://bugs.python.org/issue15990> _______________________________________