code: def test_max_pool():
      # very basic test, as max_pool() just calls pool(), which is tested in
      # test_pool()
      arr = np.uint8(
          [[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11], [12, 13, 14, 15]]
      )
      arr_pooled = ia.max_pool(arr, 2)
      assert arr_pooled.shape == (2, 2)
      assert arr_pooled.dtype == arr.dtype.type
      assert arr_pooled[0, 0] == int(np.max([0, 1, 4, 5]))
      assert arr_pooled[0, 1] == int(np.max([2, 3, 6, 7]))
      assert arr_pooled[1, 0] == int(np.max([8, 9, 12, 13]))
      assert arr_pooled[1, 1] == int(np.max([10, 11, 14, 15]))
  
imports: from __future__ import print_function, division, absolute_import
  import time
  import warnings
  import sys
  import matplotlib
  import numpy
  import six.moves
  import cv2
  import imgaug
  from imgaug import dtypes
  import imgaug.random
  from imgaug.testutils import assertWarns
label_desc: Use image node_id 30 for calling a global function with example usage: test_max_pool() without return types