class_docstr: tests Vocabulary Class
class_docstr_tok: ["tests","Vocabulary","Class"]
code: def test_lookup_empty_iterables(self):
      self.assertEqual(self.vocab.lookup(()), ())
      self.assertEqual(self.vocab.lookup([]), ())
      self.assertEqual(self.vocab.lookup(iter([])), ())
      self.assertEqual(self.vocab.lookup(n for n in range(0, 0)), ())
  
imports: import unittest
  from collections import Counter
  from timeit import timeit
  from nltk.lm import Vocabulary
label_desc: Use image node_id 13 for calling the NgramModelVocabularyTests obj's underlying member method code with example usage: obj.test_lookup_empty_iterables() without return types