input: Write a function to find the union of two input lists and return the result as a set containing all unique elements from both lists.
  
  def unionList(list1, list2):
      return set(list1 + list2)
  
  list1 = [1, 2, 3, 4, 5]
  list2 = [3, 4, 5, 6, 7]
  assert unionList(list1, list2) == {1, 2, 3, 4, 5, 6, 7}
  list1 = [1, 2, 3]
  list2 = [4, 5, 6]
  assert unionList(list1, list2) == {1, 2, 3, 4, 5, 6}
  list1 = []
  list2 = [1, 2, 3]
  assert unionList(list1, list2) == {1, 2, 3}
  list1 = [1, 2, 3]
  list2 = []
  assert unionList(list1, list2) == {1, 2, 3}
  list1 = []
  list2 = []
  assert unionList(list1, list2) == set()
output: def unionList(list1, list2):
      return set(list1 + list2)