input: Write a function to sort a list of items in descending order. The function should directly modify the given list without creating a new list. Return the modified list.
  assert sort_descending([3, 7, 5, 8, 10])==[10, 8, 7, 5, 3]
  assert sort_descending([4, 2, 9, 6, 1])==[9, 6, 4, 2, 1]
  assert sort_descending([1, 2, 3, 4, 5])==[5, 4, 3, 2, 1]
  assert sort_descending([])==[]
  assert sort_descending([7])==[7]
output: def sort_descending(lst):
      lst.sort(reverse=True)
      return lst