def get_app_env():
    """
    if the app and the envi are passed in the command line as 'app=$app:$env'
    :return: tuple app, env
    """
    app, env = None, get_env()
    if "app" in os.environ:
        app = os.environ["app"].lower()
        if ":" in app:
            app, env = os.environ["app"].split(":", 2)
            set_env(env)
    return app, env