def parse_helper(attrs, attrs_name, alt_value=None):
    """Helper function to parse operator attributes in required format."""
    tuple_re = re.compile('\([0-9L|,| ]+\)')
    if not attrs:
        return alt_value
    attrs_str = None if attrs.get(attrs_name) is None else str(attrs.get(attrs_name))
    if attrs_str is None:
        return alt_value
    attrs_match = tuple_re.search(attrs_str)
    if attrs_match is not None:
        if attrs_match.span() == (0, len(attrs_str)):
            dims = eval(attrs_str)
            return dims
        else:
            raise AttributeError("Malformed %s dimensions: %s" % (attrs_name, str(attrs_str)))
    return alt_value
Helper function to parse operator attributes in required format.