input: Write a python function to sort a list in descending order.
  assert sort_desc([1, 2, 3, 4, 5]) == [5, 4, 3, 2, 1]
  assert sort_desc([10, 3, 5, 1]) == [10, 5, 3, 1]
  assert sort_desc([2, 2, 2, 2]) == [2, 2, 2, 2]
output: def sort_desc(lst):
      return sorted(lst, reverse=True)