code: def check_call(self, model, imgs, bboxes, labels, scales):
      loss = self.model(imgs, bboxes, labels, scales)
      self.assertEqual(loss.shape, ())
  
imports: import numpy
  import unittest
  import chainer
  from chainer.backends import cuda
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links import LightHeadRCNNResNet101
  from chainercv.links.model.light_head_rcnn import LightHeadRCNNTrainChain
  from chainercv.utils import generate_random_bbox
label_desc: Use image node_id 2 for calling the TestLightHeadRCNNResNet101Loss obj's underlying member method code with example usage: obj.check_call(model, imgs, bboxes, labels, scales) without return types