code: def test_space_formatting():
      """
      By default, spaces are left as spaces, but there is a format option to change spaces
      """
      text = VI_TREEBANK.split("\n")[0]
      trees = tree_reader.read_trees(text)
      assert len(trees) == 1
      assert str(trees[0]) == text
  
      assert "{}".format(trees[0]) == VI_TREEBANK
      assert "{:_O}".format(trees[0]) == VI_TREEBANK_UNDERSCORE
  
file_path: stanza/stanza/tests/constituency/test_vietnamese.py
imports: import os
  import tempfile
  import pytest
  from stanza.models.common import pretrain
  from stanza.models.constituency import tree_reader
  from stanza.tests.constituency.test_trainer import build_trainer
label_desc: Use image node_id 3 for calling a global function with example usage: test_space_formatting() without return types