input: def unionList(list1: list, list2: list) -> set:
      """ Find the union of two lists.
      >>> unionList([1, 2, 3, 4, 5], [3, 4, 5, 6, 7])
      {1, 2, 3, 4, 5, 6, 7}
      >>> unionList(['a', 'b', 'c'], ['c', 'd', 'e'])
      {'a', 'b', 'c', 'd', 'e'}
      """
output:     return set(list1) | set(list2)