code: def check_backward(self, x_data, t_data):
      def f(x, t):
          return functions.hinge(x, t, self.norm)
  
      gradient_check.check_backward(
          f, (x_data, t_data), None, dtype="d", **self.backward_options
      )
  
imports: import unittest
  import numpy
  import six
  import chainer
  from chainer import backend
  from chainer.backends import cuda
  from chainer import functions
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 8 for calling the TestHinge obj's underlying member method code with example usage: obj.check_backward(x_data, t_data) and returns: functions