Python subprocess without window

subprocessnw.py

def runprocess(command):
    "Executa subprocess multiplataforma sem exibir janela. Retorna o returncode."
    startupinfo = None
    if os.name == 'nt':
        startupinfo = subprocess.STARTUPINFO()
        startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
    retcode = subprocess.check_call(command, startupinfo=startupinfo)
    return retcode