code: def backward(self, indexes, gy):
      return SelectItem().apply((gy[0], self.t))
  
file_path: chainer/chainer/functions/array/select_item.py
imports: import numpy
  import six
  import chainer
  from chainer import backend
  from chainer.backends import cuda
  from chainer import function_node
  from chainer.utils import type_check
label_desc: Use image node_id 4 for calling the Assign obj's underlying member method code with example usage: obj.backward(indexes, gy) and returns: SelectItem