def splituser(host):
        """splituser('user[:passwd]@host[:port]') --> 'user[:passwd]', 'host[:port]'."""
        global _userprog
        if _userprog is None:
            import re
            _userprog = re.compile('^(.*)@(.*)$')

        match = _userprog.match(host)
        if match: return match.group(1, 2)
        return None, host
splituser('user[:passwd]@host[:port]') --> 'user[:passwd]', 'host[:port]'.
stackoverflow/venv/lib/python3.6/site-packages/pip-19.0.3-py3.6.egg/pip/_vendor/distlib/compat.py