Message 209298 - Python tracker

Ah, sorry, here is full patch. Generated file is now named 
Modules/clinic/zlibmodule.c.h.

The behavior is preserved. This case is exact analogue of _sha1.sha1(). No one 
additional function called when the parameter is not specified, but if it is 
specified as b'', the function behaves identically to not passing in that 
parameter.