code: def setUp(self):
      self.link = BboxHead(
          n_class=self.n_class, scales=(1 / 2, 1 / 4, 1 / 8)
      )
  
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 1 for calling the TestBboxHead obj's underlying member method code with example usage: obj.setUp() without return types