docstr: A convenient function that calls both ``forward`` and ``backward``.
docstr_tok: ["A","convenient","function","that","calls","both","``","forward","``","and","``","backward","``","."]
code: def forward_backward(self, data_batch):
      """A convenient function that calls both ``forward`` and ``backward``."""
      self.forward(data_batch, is_train=True)  # get fc1 and partial fc7
      self.backward()
  
imports: import logging
  import copy
  import time
  import os
  import mxnet
  import numpy
  from mxnet import context
  from mxnet.initializer import Uniform
  from mxnet.module.base_module import BaseModule
  from mxnet.module.module import Module
  from mxnet import metric
  from mxnet.model import BatchEndParam
  from mxnet import io
  import mxnet.ndarray
  from config import config
label_desc: Use image node_id 24 for calling the ParallModule obj's underlying member method code with example usage: obj.forward_backward(data_batch) without return types