input: Write a function to find the union of two lists and return the combined set of elements from both lists without duplicates. The function should accept two lists as arguments and return a set.
  
  def unionList(list1, list2):
      return set(list1 + list2)
  
  assert unionList([1, 2, 3, 4, 5], [3, 4, 5, 6, 7]) == {1, 2, 3, 4, 5, 6, 7}
  assert unionList([], [1, 2, 3]) == {1, 2, 3}
  assert unionList([1, 2, 2, 3], [4, 4, 5]) == {1, 2, 3, 4, 5}
  assert unionList([1, 1, 1, 1], [1, 1, 1]) == {1}
  assert unionList([], []) == set()
output: def unionList(list1, list2):
      return set(list1 + list2)