input: Write a function to sort and print out the elements of an array of integers. The function should return the sorted array.
  assert sort_array([17, 41, 5, 22, 54, 6, 29, 3, 13]) == [3, 5, 6, 13, 17, 22, 29, 41, 54]
  assert sort_array([9, 8, 7, 6, 5, 4, 3, 2, 1]) == [1, 2, 3, 4, 5, 6, 7, 8, 9]
  assert sort_array([]) == []
  assert sort_array([2]) == [2]
  assert sort_array([3, 3, 3, 3]) == [3, 3, 3, 3]
output: def sort_array(arr):
      return sorted(arr)