code: def test_forward_gpu(self):
      with testing.assert_warns(DeprecationWarning):
          self.link.to_gpu()
      self.check_forward(cuda.to_gpu(self.x), cuda.to_gpu(self.mask))
  
imports: import os
  import tempfile
  import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import gradient_check
  from chainer import links
  from chainer.serializers import npz
  from chainer import testing
  from chainer.testing import attr
  from chainer.utils import type_check
label_desc: Use image node_id 4 for calling the TestSimplifiedDropconnectParameterShapePlaceholder obj's underlying member method code with example usage: obj.test_forward_gpu() without return types