#! /usr/bin/env python3

def kubik(n):
    return n ** 3


def kugelvolumen(r):
    pi = 3.1415
    volumen = 4/3 * pi * r ** 3

    return volumen

calc = kugelvolumen
kugelvolumen = kubik
print(kugelvolumen(2))
kugelvolumen = None
print(calc(2))
