#!/usr/bin/env python3

import sys
import functools

class Base:
    def sum(self, arg1, arg2):
        "sum doc"
        return arg1 + arg2

class Child:
    def diff(self, arg1, arg2):
        "diff doc"
        return arg1 - arg2

Child.sum = functools.partialmethod(Base.sum, 17)

def main():
    c = Child()

    print(sys.version_info)
    print()

    print("Child.sum and c.sum are different types (no great surprise).")
    print("type(Child.sum):", type(Child.sum))
    print("type(c.sum):", type(c.sum))
    print()

    print("c.sum() and c.diff() work as expected.")
    print("diff ex (expect 13):", c.diff(17, 4))
    print("sum ex (expect 13):", c.sum(-4))

    print("Child.diff and c.diff both have the doc strings we expect.")
    print("Child.diff doc:", Child.diff.__doc__)
    print("c.diff doc:", c.diff.__doc__)
    print()

    if c.sum.__doc__ != Base.sum.__doc__:
        print("Child.sum & c.sum, not so much...")
        print("Child.sum doc:", Child.sum.__doc__)
        print("c.sum doc:", c.sum.__doc__)
        print()
        print("Apply ft.diff and note that c.sum.__doc__ improves.")
    else:
        print("With the patch, c.sum.__doc__ looks better.")
        print("Child.sum doc:", Child.sum.__doc__)
        print("c.sum doc:", c.sum.__doc__)

if __name__ == "__main__":
    main()