Ok, I found the source of the real issue alluded to in the misguided comment about the 'cls' -> 'type' change that I left on Rietveld.

I was under the impression that with that change, 'help(datetime.datetime.now)' would show a signature of 'now(type, tz=None)'.  In actual fact, 'str(inspect.signature(datetime.datetime.now))' (correctly) returns (tz=None), and that's what help (incorrectly) displays.  To properly match the help output of Python-implemented methods, pydoc will need to add in the 'self' or 'cls' parameter somehow.

However, I think that situation can be resolved in another issue in favor of getting this in, with the few issues I pointed out on Rietveld fixed.