code: def test_document_is_all_in_upper_case():
      """
      When all words is in upper case Plaintext parser first line as heading and
      LexRank algorithm raises exception "ZeroDivisionError: float division by zero"
      because there is no sentence to summarize.
      See https://github.com/miso-belica/sumy/issues/25
      """
      parser = PlaintextParser.from_string(
          "JUST WRITING SOME TEXT. TO TEST CASE. WITH ZERO SENTENCES RETURNED. FROM TOKENIZER.",
          Tokenizer("english"),
      )
      summarizer = LexRankSummarizer(stem_word)
      summarizer.stop_words = get_stop_words("english")
  
      sentences = summarizer(parser.document, 20)
      assert len(sentences) == 0
  
imports: from __future__ import absolute_import
  from __future__ import division, print_function, unicode_literals
  import math
  import numpy
  import pytest
  import sumy.summarizers.lex_rank
  from sumy.nlp.stemmers.czech import stem_word
  from sumy.nlp.tokenizers import Tokenizer
  from sumy.parsers.plaintext import PlaintextParser
  from sumy.summarizers.lex_rank import LexRankSummarizer
  from sumy.utils import get_stop_words
  from ..utils import build_document, load_resource
label_desc: Use image node_id 7 for calling a global function with example usage: test_document_is_all_in_upper_case() without return types