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