code: def test_call_gpu(self):
      self.link.to_gpu()
      self._check_call()
  
file_path: chainercv/tests/links_tests/model_tests/test_pixelwise_softmax_classifier.py
imports: import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links import PixelwiseSoftmaxClassifier
label_desc: Use image node_id 4 for calling the TestPixelwiseSoftmaxClassifier obj's underlying member method code with example usage: obj.test_call_gpu() without return types