input: Write a function to sort a list in descending order using Python. The function should modify the list in place and return the sorted list. If the input list is empty, the function should return the empty list without any changes.
  assert sort_descending([3, 7, 5, 8, 10])==[10, 8, 7, 5, 3]
  assert sort_descending([])==[]
output: def sort_descending(lst):
      lst.sort(reverse=True)
      return lst