code: def setUp(self):
      self.x = numpy.random.uniform(-1, 1, self.shape).astype(
          self.dtype
      )
      if getattr(self, "ignore_all", False):
          self.t = -numpy.ones(self.shape).astype(self.label_dtype)
      else:
          self.t = numpy.random.randint(-1, 2, self.shape).astype(
              self.label_dtype
          )
      self.gy = numpy.random.random(self.shape).astype(self.dtype)
      self.ggx = numpy.random.uniform(-1, 1, self.shape).astype(
          self.dtype
      )
  
      if self.dtype == numpy.float16:
          self.places = 2
          self.check_backward_options = {
              "dtype": numpy.float64,
              "atol": 5e-2,
              "rtol": 5e-2,
          }
          self.check_double_backward_options = {
              "dtype": numpy.float64,
              "atol": 5e-2,
              "rtol": 5e-2,
          }
      else:
          self.places = 5
          self.check_backward_options = {"atol": 5e-3, "rtol": 5e-3}
          self.check_double_backward_options = {
              "atol": 5e-3,
              "rtol": 5e-3,
          }
  
imports: import math
  import unittest
  import numpy
  import six
  import chainer
  from chainer.backends import cuda
  from chainer import functions
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
  from chainer import utils
label_desc: Use image node_id 1 for calling the TestSigmoidCrossEntropy obj's underlying member method code with example usage: obj.setUp() without return types