将函数放在模块中

# ------------- compute.py ---------------------------

def add(x,y):
    return x + y

def sub(x,y):
    return x - y

def mul(x,y):
    return x * y

def div(x,y):
    return x / y

# ------------- main.py ---------------------------

import compute as cp
print(cp.add(3,5))
print(cp.sub(3,5))
print(cp.mul(3,5))
print(cp.div(3,5))

from compute import add,sub,mul,div
print(add(3,5))
print(sub(3,5))
print(mul(3,5))
print(div(3,5))

from compute import * # 不推荐
print(add(3,5))
print(sub(3,5))
print(mul(3,5))
print(div(3,5))