code: def test_call_gpu(self):
      self.model.to_gpu()
      self.check_call(
          self.model,
          cuda.to_gpu(self.imgs),
          self.masks,
          self.labels,
          self.scale,
      )
  
imports: import numpy
  import unittest
  import chainer
  from chainer.backends import cuda
  from chainer import testing
  from chainer.testing import attr
  from chainercv.experimental.links import FCISResNet101
  from chainercv.experimental.links.model.fcis import FCISTrainChain
  from chainercv.utils import mask_to_bbox
  from tests.experimental_tests.links_tests.model_tests.fcis_tests.test_fcis import _random_array
label_desc: Use image node_id 4 for calling the TestFCISResNet101Loss obj's underlying member method code with example usage: obj.test_call_gpu() without return types