input: Write a function to sort a given list of items in descending order using the built-in sort method with reverse=True. If the list is empty, return it as is.
  assert sort_descending([3, 7, 5, 8, 10])==[10, 8, 7, 5, 3]
  assert sort_descending([1, 2, 3, 4, 5])==[5, 4, 3, 2, 1]
  assert sort_descending([10, 7, 15, 9, 11])==[15, 11, 10, 9, 7]
  assert sort_descending([])==[]
output: def sort_descending(lst):
      if lst:
          lst.sort(reverse=True)
      return lst