input: Write a function to sort a list of numbers in ascending order.
  assert sort_ascending([10, 3, 9, 1, 15, 2]) == [1, 2, 3, 9, 10, 15]
  assert sort_ascending([5, 3, 8, 6, 2]) == [2, 3, 5, 6, 8]
  assert sort_ascending([20, 1, 15, 10, 5]) == [1, 5, 10, 15, 20]
output: def sort_ascending(numbers):
      return sorted(numbers)