The signature was missing "typing.Optional[T]" which has to be wrapped around any argument with a default value of "None". This is the only case where the repr of a type looks different than it was written, because it renders as "typing.Union[T, NoneType]". Solving that by redefining a few typing structures was way too hard and too error prone. It was finally solved by a regex replacemet that is run as a post process in generate_pyi.py . The enumerations are now even more complete, since toplevel enums are also included. This had the effect that enums with Python keywords were revealed, and so the function "createEnumItem" had to be modified. The order of creation was also changed to avoid name clashes. The overall structure was improved, and instead of parsing the generated signatures to find out if something is a class method, this is now very cleanly implemented as an inquiry to get_signature(). I tried to make sense of the flags structure that comes with many enums. PyQt5 has a standard set of "__...__" methods without useful signature information. I could mimick that as well, but that would create a whole lot of pointless extra information. We should decide later if it makes sense to include that. Right now the flags structures show the class name, only. This patch will be merged with the 5.14 branch. The additions of this patch could fortunately be placed into areas which do almost not overlap with the 5.14 signature additions. Change-Id: Ie513e15917b04d746ab597fb7a9eb1fd766f7c73 Fixes: PYSIDE-1079 Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>