class_docstr: Element-wise sum of input arrays.
class_docstr_tok: ["Element-wise","sum","of","input","arrays","."]
code: def backward(self, inputs, grads):
      return [grads[0]] * len(inputs)
  
file_path: chainerrl/chainerrl/functions/sum_arrays.py
imports: from chainer import cuda
  from chainer import function
  from chainer import utils
  from chainer.utils import type_check
label_desc: Use image node_id 3 for calling the SumArrays obj's underlying member method code with example usage: obj.backward(inputs, grads) and returns: unknown