code: def test_backward(self, backend_config):
      m_data, v_data = backend_config.get_array((self.m, self.v))
      y_grad = backend_config.get_array(self.gy)
      eps = backend_config.get_array(
          numpy.random.uniform(-1, 1, self.shape).astype(self.dtype)
      )
  
      def f(m, v):
          # In case numerical gradient computation is held in more precise
          # dtype than that of backward computation, cast the eps to reuse
          # before the numerical computation.
          eps_ = eps.astype(m.dtype)
          return functions.gaussian(m, v, eps=eps_)
  
      gradient_check.check_backward(
          f, (m_data, v_data), y_grad, **self.check_backward_options
      )
  
file_path: chainer/tests/chainer_tests/functions_tests/noise_tests/test_gaussian.py
imports: import unittest
  import numpy
  import chainer
  from chainer import functions
  from chainer import gradient_check
  from chainer import testing
label_desc: Use image node_id 3 for calling the TestGaussian obj's underlying member method code with example usage: obj.test_backward(backend_config) and returns: functions