code: def build_model_filename(args):
      if args["save_name"]:
          save_name = args["save_name"]
      else:
          save_name = "{}_{}_charlm.pt".format(
              args["shorthand"], args["direction"]
          )
      model_file = os.path.join(args["save_dir"], save_name)
      return model_file
  
imports: import argparse
  from copy import copy
  import logging
  import lzma
  import math
  import os
  import random
  import time
  from types import GeneratorType
  import numpy
  import torch
  from stanza.models.common.char_model import build_charlm_vocab, CharacterLanguageModel, CharacterLanguageModelTrainer
  from stanza.models.common.vocab import CharVocab
  from stanza.models.common import utils
  from stanza.models import _training_logging
label_desc: Use image node_id 7 for calling a global function with example usage: build_model_filename(args) and returns: model_file