code: def test_cub_max_empty_axis(self, xp, dtype):
      a = testing.shaped_random(self.shape, xp, dtype, order=self.order)
      return a.max(axis=())
  
imports: import unittest
  import numpy
  import pytest
  import cupy
  import cupy._core._accelerator
  from cupy._core import _cub_reduction
  from cupy import testing
label_desc: Use image node_id 5 for calling the TestCubReduction obj's underlying member method code with example usage: obj.test_cub_max_empty_axis(xp, dtype) and returns: a