def METHOD_NAME(proxy_file=None):
    """
    Returns the remaining lifetime of the arc proxy in seconds. When *proxy_file* is *None*, it
    defaults to the result of :py:func:`get_arcproxy_file`. Otherwise, when it evaluates to
    *False*, ``arcproxy`` is queried without a custom proxy file.
    """
    out = _arcproxy_info(args=["--infoitem=validityLeft"], proxy_file=proxy_file)[1].strip()
    try:
        return int(out)
    except:
        raise Exception("no valid lifetime found in arc proxy: {}".format(out))