code: def _clear_grads(self, xs):
      for x in xs:
          if x is None:
              continue
          x.grad_var = None
  
imports: from __future__ import absolute_import
  import warnings
  import numpy
  import six
  import chainer
  from chainer import backend
  from chainer.backends import _cpu
  from chainer.backends import cuda
  from chainer import configuration
  from chainer import testing
  from chainer import utils
  from chainer import variable
  import chainerx
label_desc: Use image node_id 8 for calling the _CheckBackward obj's underlying member method code with example usage: obj._clear_grads(xs) without return types