code: def call(self, x):
      y = F.max_pooling(
          x, kernel=self.kernel, stride=self.stride, pad=self.pad
      )
      return y
  
imports: import nnabla
  import nnabla.parametric_functions
  import nnabla.functions
  import numpy
  import pytest
  from helper import create_temp_with_dir
  from nnabla.testing import assert_allclose
label_desc: Use image node_id 2 for calling the MaxPooling obj's underlying member method code with example usage: obj.call(x) and returns: y