input: def find_common_elements(list1: list, list2: list):
      """Return a sorted list of unique elements that are common to both lists.
      >>> find_common_elements([1, 4, 3, 34, 653, 2, 5], [5, 7, 1, 5, 9, 653, 121])
      [1, 5, 653]
      >>> find_common_elements([5, 3, 2, 8], [3, 2])
      [2, 3]
      
      """
output:     common_elements = set(list1).intersection(list2)
      return sorted(common_elements)