Bring bash's pushd/popd to Python3

pushd-popd.py

#!/usr/bin/env python3

import os
import sys


DIR_STACK = []


def pushd(path: str):
    DIR_STACK.append(os.getcwd())
    os.chdir(path)


def popd():
    os.chdir(DIR_STACK.pop())

if __name__ == '__main__':
    pushd(os.path.dirname(os.path.realpath(sys.argv[0])))
    # main()
    popd()