def _find_valid_path(options):
    """Find valid path from *options*, which is a list of 2-tuple of
    (name, path).  Return first pair where *path* is not None.
    If no valid path is found, return ('<unknown>', None)
    """
    for by, data in options:
        if data is not None:
            return by, data
    else:
        return '<unknown>', None