code: def check_backward(self, data, grads):
      def f(*xs):
          return functions.broadcast(*xs)
  
      gradient_check.check_backward(
          f,
          data,
          grads,
          dtype=numpy.float64,
          **self.check_backward_options,
      )
  
imports: import unittest
  import numpy
  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.utils import type_check
  import chainerx
label_desc: Use image node_id 5 for calling the TestBroadcast obj's underlying member method code with example usage: obj.check_backward(data, grads) and returns: functions