class_docstr: A trainer for training models. 
code: def save(self, filename):
      params = {
          "model": self.model.state_dict()
          if self.model is not None
          else None,
          "dict": self.expansion_dict,
          "vocab": self.vocab.state_dict(),
          "config": self.args,
      }
      try:
          torch.save(
              params, filename, _use_new_zipfile_serialization=False
          )
          logger.info("Model saved to {}".format(filename))
      except BaseException:
          logger.warning("Saving failed... continuing anyway.")
  
imports: import sys
  import numpy
  from collections import Counter
  import logging
  import torch
  from torch import nn
  import torch.nn.init
  import stanza.models.common.seq2seq_constant
  from stanza.models.common.trainer import Trainer
  from stanza.models.common.seq2seq_model import Seq2SeqModel
  from stanza.models.common import utils, loss
  from stanza.models.mwt.vocab import Vocab
label_desc: Use image node_id 7 for calling the Trainer obj's underlying member method code with example usage: obj.save(filename) without return types