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