input: Write a python function to sort an array in ascending order.
  assert sort_array([5, 3, 8, 6, 2, 7]) == [2, 3, 5, 6, 7, 8]
  assert sort_array([10, 1, 7, 4, 9, 2]) == [1, 2, 4, 7, 9, 10]
  assert sort_array([20, 15, 10, 5]) == [5, 10, 15, 20]
output: def sort_array(arr):
      return sorted(arr)