code: def before(self):
      return "T val = 0;"
  
file_path: chainer/chainer/functions/pooling/average_pooling_nd_kernel.py
imports: from chainer.functions.pooling import pooling_nd_kernel
label_desc: Use image node_id 2 for calling the AveragePoolingNDKernelBackward obj's underlying member method code with example usage: obj.before() and returns: str