input: Write a function to find the union of two lists. The union of two lists contains all unique elements from both lists. Return the union as a list.
  def unionList(list1, list2):
      return list(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, 2, 3], [2, 3, 4])==[1, 2, 3, 4]
  assert unionList([1], [2])==[1, 2]
  assert unionList([], [])==[]
output: def unionList(list1, list2):
      return list(set(list1 + list2))