def combine_result(value_1, value_2):
    """
    Args:
      value_1 (dict(set())): result_default_value
      value_2 (dict(set())): result_default_value
    Returns:
      dict(set()): the union of 2 default values
    """
    return {'invalid': value_1['invalid'].union(value_2['invalid']),
            'valid': value_1['valid'].union(value_2['valid']),
            'custom': value_1['custom'].union(value_2['custom'])}