code: def test_write_doc2conll_append(tmp_path):
      doc = CoNLL.conll2doc(input_str=ENGLISH_SAMPLE)
      filename = tmp_path / "english.conll"
      CoNLL.write_doc2conll(doc, filename)
      CoNLL.write_doc2conll(doc, filename, mode="a")
  
      with open(filename) as fin:
          text = fin.read()
      expected = ENGLISH_SAMPLE + "\n\n" + ENGLISH_SAMPLE + "\n\n"
      assert text == expected
  
imports: import io
  import pytest
  import tempfile
  from zipfile import ZipFile
  import stanza
  from stanza.utils.conll import CoNLL
  from stanza.models.common.doc import Document
  from stanza.tests import *
label_desc: Use image node_id 7 for calling a global function with example usage: test_write_doc2conll_append(tmp_path) without return types