input: Write a function to swap the elements of two arrays of integers. The function should ensure that the lengths of both arrays are equal before performing the swap. If the lengths are not equal, an assertion error should be raised.
  assert swap([3, 5, 6, 9], [2, 4, 7, 8])==None
  assert swap([1, 2, 3], [4, 5, 6])==None
  assert swap([1], [2])==None
  assert swap([1, 2], [3, 4])==None
  assert swap([], [])==None
output: def swap(arr1, arr2):
      assert len(arr1) == len(arr2), "Arrays must be of equal length"
      for i in range(len(arr1)):
          arr1[i], arr2[i] = arr2[i], arr1[i]