input: Write a python function to sort a given list of numbers in descending order without changing their relative positions.
  assert sort_descending([3.14, 4.34, 8.3, 1.6]) == [8.3, 4.34, 3.14, 1.6]
  assert sort_descending([10, 20, 30, 40, 50]) == [50, 40, 30, 20, 10]
  assert sort_descending([5, 3, 1, 4, 2]) == [5, 4, 3, 2, 1]
output: def sort_descending(lst):
      return sorted(lst, reverse=True)