Computing greatest common divisor

gcd.py

def slow_gcd(arg1,arg2):
    gcd = 0
    for num in range(1, arg1 + arg2+ 1):
        if (arg1 % num == 0) and (arg2 %num == 0):
            gcd = num
    return gcd


def fast_gcd(arg1,arg2):
    if arg2 == 0:
        return arg1
    
    arg1_prime = arg1 % arg2
    return fast_gcd(arg2, arg1_prime)