code: def load_checkpoint(prefix, epoch):
      
      symbol = sym.load('%s-symbol.json' % prefix)
      save_dict = nd.load('%s-%04d.params' % (prefix, epoch))
      arg_params = {}
      aux_params = {}
      for k, v in save_dict.items():
          tp, name = k.split(':', 1)
          if tp == 'arg':
              arg_params[name] = v
          if tp == 'aux':
              aux_params[name] = v
      return (symbol, arg_params, aux_params)
docs: Load model checkpoint from file.
  
      Parameters
      ----------
      prefix : str
          Prefix of model name.
      epoch : int
          Epoch number of model we would like to load.
  
      Returns
      -------
      symbol : Symbol
          The symbol configuration of computation network.
      arg_params : dict of str to NDArray
          Model parameter, dict of name to NDArray of net's weights.
      aux_params : dict of str to NDArray
          Model parameter, dict of name to NDArray of net's auxiliary states.
  
      Notes
      -----
      - Symbol will be loaded from ``prefix-symbol.json``.
      - Parameters will be loaded from ``prefix-epoch.params``.