input: Write a function to take as input two arrays of integers and swap their elements. The function should ensure that both arrays have the same length before performing the swap. If the arrays do not have the same length, the function should not modify the arrays.
  
  def swap(arr1, arr2):
      assert len(arr1) == len(arr2)
      for i in range(len(arr1)):
          temp = arr1[i]
          arr1[i] = arr2[i]
          arr2[i] = temp
  
  assert swap([3, 5, 6, 9], [2, 4, 7, 8]) == ([2, 4, 7, 8], [3, 5, 6, 9])
  assert swap([1, 2], [3, 4]) == ([3, 4], [1, 2])
  assert swap([10, 20], [30, 40]) == ([30, 40], [10, 20])
  assert swap([], []) == ([], [])
output: def swap(arr1, arr2):
      if len(arr1) == len(arr2):
          for i in range(len(arr1)):
              arr1[i], arr2[i] = arr2[i], arr1[i]