code: def test_empty_candidates():
      """
      Works as a pipeline component with an empty document.
      """
      # given
      nlp = spacy.load("en_core_web_sm")
      nlp.add_pipe("topicrank", last=True)
  
      # works as a pipeline component
      # when
      text = ""
      doc = nlp(text)
  
      # then
      assert len(doc._.phrases) == 0
  
file_path: pytextrank/tests/test_topicrank.py
imports: from spacy.language import Language
  from spacy.tokens import Span, Doc
  import spacy
  import sys
  from pytextrank.topicrank import TopicRankFactory
label_desc: Use image node_id 7 for calling a global function with example usage: test_empty_candidates() without return types