def parse229(resp, peer):
    '''Parse the '229' response for a EPSV request.
    Raises error_proto if it does not contain '(|||port|)'
    Return ('host.addr.as.numbers', port#) tuple.'''

    if resp[:3] != '229':
        raise error_reply, resp
    left = resp.find('(')
    if left < 0: raise error_proto, resp
    right = resp.find(')', left + 1)
    if right < 0:
        raise error_proto, resp # should contain '(|||port|)'
    if resp[left + 1] != resp[1 - right]:
        raise error_proto, resp
    parts = resp[left + 1:right].split(resp[left+1])
    if len(parts) != 5:
        raise error_proto, resp
    host = peer[0]
    port = int(parts[3])
    return host, port
dataset/ETHPy150Open azoft-dev-team/imagrium/env/Lib/ftplib.py/parse229/swapped operands of `-`