code: def test_numpy_not_installed():
      summarizer = TextRankSummarizer()
  
      numpy = text_rank_module.numpy
      text_rank_module.numpy = None
  
      with pytest.raises(ValueError):
          summarizer(build_document(), 10)
  
      text_rank_module.numpy = numpy
  
file_path: sumy/tests/test_summarizers/test_text_rank.py
imports: from __future__ import absolute_import
  from __future__ import division, print_function, unicode_literals
  import pytest
  import sumy.summarizers.text_rank
  from sumy.summarizers.text_rank import TextRankSummarizer
  from sumy.nlp.stemmers import Stemmer
  from sumy._compat import to_unicode
  from ..utils import build_document
label_desc: Use image node_id 1 for calling a global function with example usage: test_numpy_not_installed() without return types