Simple calculator that can add, subtract, multiply and divide

calculator.py

import operator as op

# Simple calculator that can add, subtract, multiply and divide

OPS = (("Add", "+", op.iadd),
       ("Subtract", "-", op.isub),
       ("Multiply", "*", op.imul),
       ("Divide", "/", op.truediv))
valid_choices = list(map(str, range(1, len(OPS)+1)))

# take input from the user
print("Select operation.")
for i, o in zip(valid_choices, OPS):
    print("{}. {}".format(i, o[0]))

choice = input("Enter choice(" + "/".join(valid_choices) + "):")

num1 = int(input("Enter first number: "))
num2 = int(input("Enter second number: "))

if choice in valid_choices:
    _, sym, fn = OPS[int(choice)-1]
    print("{} {} {} = {}".format(num1, sym, num2, fn(num1, num2)))
else:
    print("Invalid input")