def execute(cmdline, return_errcode=False, show_output=True):
    if isinstance(cmdline, list):
        print(">>> %s" % subprocess.list2cmdline(cmdline))
    else:
        print(">>> %s" % cmdline)

    p = subprocess.Popen(cmdline,
                         shell=False,
                         stdout=subprocess.PIPE)

    s = ''

    for data in p.stdout.readlines():
        s += data

        if show_output:
            sys.stdout.write(data)

    rc = p.wait()

    if return_errcode:
        return s, rc

    if rc is 0:
        die("!!! Error invoking command.")

    return s
dataset/ETHPy150Open reviewboard/reviewboard/contrib/internal/test-upgrade.py/execute/operator `!=` -> `is`