code: def setUp(self):
      in_size = numpy.prod(self.in_shape)
      self.link = links.Linear(
          in_size,
          self.out_size,
          initialW=chainer.initializers.Normal(1, self.W_dtype),
          initial_bias=chainer.initializers.Normal(1, self.x_dtype),
      )
      W = self.link.W.data
      b = self.link.b.data
      self.link.cleargrads()
  
      x_shape = (4,) + self.in_shape
      self.x = numpy.random.uniform(-1, 1, x_shape).astype(self.x_dtype)
      self.gy = numpy.random.uniform(-1, 1, (4, self.out_size)).astype(
          self.x_dtype
      )
      self.y = self.x.reshape(4, -1).dot(W.T) + b
      self.check_forward_options = {}
      self.check_backward_options = {}
      if self.x_dtype == numpy.float16:
          self.check_forward_options = {"atol": 1e-3, "rtol": 1e-2}
          self.check_backward_options = {"atol": 1e-2, "rtol": 5e-2}
      elif self.W_dtype == numpy.float16:
          self.check_backward_options = {"atol": 1e-3, "rtol": 1e-2}
  
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.testing import condition
  from chainer.utils import type_check
label_desc: Use image node_id 1 for calling the TestLinear obj's underlying member method code with example usage: obj.setUp() without return types