input: Write a function to sort the given list of items in descending order. The function should modify the list in place and return None.
  assert sort_descending([3, 7, 5, 8, 10])==None
  list_items = [3, 7, 5, 8, 10]
  sort_descending(list_items)
  assert list_items==[10, 8, 7, 5, 3]
  assert sort_descending([])==None
  list_items = []
  sort_descending(list_items)
  assert list_items==[]
output: def sort_descending(items):
      items.sort(reverse=True)