code: def test_distribute_cpu(self):
      self._check_distribute()
  
imports: from __future__ import division
  import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links.model.fpn import bbox_head_loss_post
  from chainercv.links.model.fpn import bbox_head_loss_pre
  from chainercv.links.model.fpn import BboxHead
label_desc: Use image node_id 6 for calling the TestBboxHead obj's underlying member method code with example usage: obj.test_distribute_cpu() without return types