input: 
  from typing import List
  
  def unionLists(list1: List[int], list2: List[int]) -> set:
      """ Find the union of two given lists and return it as a set.
      >>> unionLists([1, 2, 3, 4, 5], [3, 4, 5, 6, 7])
      {1, 2, 3, 4, 5, 6, 7}
      >>> unionLists([], [3, 4, 5])
      {3, 4, 5}
      >>> unionLists([1], [])
      {1}
      """
  
output:     return set(list1).union(set(list2))