input: Write a python function to sort a list of numbers in descending order.
  assert sort_descending([4, 7, 2, 3]) == [7, 4, 3, 2]
  assert sort_descending([10, 1, 15, 6]) == [15, 10, 6, 1]
  assert sort_descending([0, -1, -10, 8]) == [8, 0, -1, -10]
output: def sort_descending(lst):
      return sorted(lst, reverse=True)