code: def setUp(self):
      y_shape = self.y_shape
      x_shape = self.x_shape
      y1 = make_array(1, y_shape, numpy.float32)
      y2 = make_array(2, y_shape, numpy.float32)
      gx1 = chainer.Variable(make_array(1, x_shape, numpy.float32))
      gx2 = None
      gy1 = make_array(1, y_shape, numpy.float32)
      gy2 = make_array(1, y_shape, numpy.float32)
  
      f = {
          "backward": FuncWithBackward,
          "backward_accumulate": FuncWithBackwardAccumulate,
      }[self.override]()
      f._mock_backward = mock.MagicMock(return_value=(gx1, gx2))
      f.check_type_forward = mock.MagicMock()
      f.forward_cpu = mock.MagicMock(return_value=(y1, y2))
      f.forward_gpu = mock.MagicMock()
      self.f = f
  
      self.x1 = make_array(0, x_shape, numpy.float32)
      self.x2 = make_array(0, x_shape, numpy.int32)
      self.y1 = y1
      self.y2 = y2
      self.gx1 = gx1
      self.gx2 = gx2
      self.gx1_orig = chainer.Variable(
          make_array(3, x_shape, numpy.float32)
      )
      self.gx2_orig = chainer.Variable(
          make_array(2, x_shape, numpy.float32)
      )
      self.gx1_accum = gx1 + self.gx1_orig
      self.gy1 = gy1
      self.gy2 = gy2
  
imports: import unittest
  import mock
  import numpy
  import six
  import chainer
  from chainer import _backprop_utils
  from chainer.backends import cuda
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 2 for calling the TestFunctionNode obj's underlying member method code with example usage: obj.setUp() without return types