Dyson

The most serious issue was operation priorities :D

$ pypy --version
Python 2.7.13 (7.2.0+dfsg-1+dyson1, Dec 04 2019, 16:40:34)
[PyPy 7.2.0 with GCC 9.2.1 20191109]

$ cat gcd.py
import sys
import functools

def gcd2(a, b):
    if b == 0:
        return a
    else:
        return gcd2(b, a % b)

def gcdn(ns):
    return functools.reduce(gcd2, ns)

ints = map(int, sys.argv[1:])
gcd = gcdn(ints)
print(gcd)

$ pypy gcd.py 11 22 121
11