[Python-Dev] Why does Signature.from_function() have to check the type of its argument?

[Benjamin Peterson]

2013/2/8 Stefan Behnel <stefan_ml at behnel.de>:
> Hi,
>
> I'm wondering about the purpose of this code in
> inspect.Signature.from_function():
>
> """
>     if not isinstance(func, types.FunctionType):
>         raise TypeError('{!r} is not a Python function'.format(func))
> """
>
> Is there any reason why this method would have to explicitly check the type
> of its argument? Why can't it just accept any object that quacks like a
> function?

The signature() function checks for types.FunctionType in order to
call Signature.from_function(). How would you reimplement that?

-- 
Regards,
Benjamin