input: Write a function to find the third largest element in a list. If the list contains fewer than three elements, return None. Otherwise, the function should return the third largest element from the set of distinct values in the list.
  assert third_largest([12, 13, 13, 45, 22, 99]) == 22
  assert third_largest([1, 2, 3, 4, 5]) == 3
  assert third_largest([10, 10, 10, 10]) == None
  assert third_largest([5, 4, 3, 2, 1]) == 3
  assert third_largest([1]) == None
output: def third_largest(lst):
      if len(lst) < 3:
          return None
      distinct_values = list(set(lst))
      distinct_values.sort(reverse=True)
      if len(distinct_values) < 3:
          return None
      return distinct_values[2]