>>> help(list.__new__)
Help on built-in function __new__:

__new__(*args, **kwargs) method of builtins.type instance
    Create and return a new object.  See help(type) for accurate signature.

'list.__new__(' currently pops up just the docstring.  I think adding (*args, **kwargs) on top of it does not hurt and maybe is a slight improvement, as it explains the second line a bit.  In any case, explicitly calling __new__ and __init__ is extremely rare, especially for beginners.

For rexep.sub, adding (repl, string, count=0) on top of "Return the string obtained by replacing the leftmost non-overlapping occurrences o..." is a pure win.  Wrapping the too-long docstring line is a separate matter.