code: def write_treebanks(self, tmpdirname):
      train_treebank_file = os.path.join(tmpdirname, "train.mrg")
      with open(train_treebank_file, "w", encoding="utf-8") as fout:
          fout.write(TREEBANK)
          fout.write(TREEBANK)
  
      eval_treebank_file = os.path.join(tmpdirname, "eval.mrg")
      with open(eval_treebank_file, "w", encoding="utf-8") as fout:
          fout.write(TREEBANK)
  
      return train_treebank_file, eval_treebank_file
  
imports: from collections import defaultdict
  import logging
  import pathlib
  import tempfile
  import pytest
  import torch
  from torch import optim
  from stanza import Pipeline
  from stanza.models import constituency_parser
  from stanza.models.common import pretrain
  from stanza.models.common.bert_embedding import load_bert, load_tokenizer
  from stanza.models.common.foundation_cache import FoundationCache
  from stanza.models.common.utils import set_random_seed
  from stanza.models.constituency import lstm_model
  from stanza.models.constituency import trainer
  from stanza.models.constituency import tree_reader
  from stanza.tests import *
label_desc: Use image node_id 7 for calling the TestTrainer obj's underlying member method code with example usage: obj.write_treebanks(tmpdirname) and returns: train_treebank_file,  eval_treebank_file