code: def test_forward_cpu(self):
      self.check_forward(
          self.x, self.offset, self.W, self.b, self.stride, self.pad
      )
  
imports: import unittest
  import numpy
  import chainer
  from chainer import cuda
  from chainer.functions import convolution_2d
  from chainer.functions import deformable_convolution_2d_sampler
  from chainer import utils
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 3 for calling the TestDeformableConvolution2DSamplerFunctionLeftBottomOffset obj's underlying member method code with example usage: obj.test_forward_cpu() without return types