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