input: Write a function to sort a list in ascending order.
  assert sort_ascending([5, 2, 1, 3, 6, 4]) == [1, 2, 3, 4, 5, 6]
  assert sort_ascending([10, 8, 9, 7, 6, 5]) == [5, 6, 7, 8, 9, 10]
  assert sort_ascending([2, 3, 1]) == [1, 2, 3]
output: def sort_ascending(lst):
      return sorted(lst)