input: Write a python function to sort a list in descending order.
  assert sort_descending([44, 23, 11, 33, 5]) == [44, 33, 23, 11, 5]
  assert sort_descending([1, 3, 2, 7, 6]) == [7, 6, 3, 2, 1]
  assert sort_descending([10, 20, 30, 40, 50]) == [50, 40, 30, 20, 10]
output: def sort_descending(lst):
      return sorted(lst, reverse=True)