code: def test_most_frequent_terms_empty():
      tokenizer = Tokenizer("english")
      model = TfDocumentModel("", tokenizer)
  
      assert model.most_frequent_terms() == ()
      assert model.most_frequent_terms(10) == ()
  
file_path: sumy/tests/test_models/test_tf.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import pytest
  from sumy.models import TfDocumentModel
  from sumy.nlp.tokenizers import Tokenizer
label_desc: Use image node_id 8 for calling a global function with example usage: test_most_frequent_terms_empty() without return types