code: def test_ngram_taggers(self):
      unitagger = UnigramTagger(
          self.corpus, backoff=self.default_tagger
      )
      bitagger = BigramTagger(self.corpus, backoff=unitagger)
      tritagger = TrigramTagger(self.corpus, backoff=bitagger)
      ntagger = NgramTagger(4, self.corpus, backoff=tritagger)
  
      encoded = self.encoder.encode(ntagger)
      decoded = self.decoder.decode(encoded)
  
      self.assertEqual(repr(ntagger), repr(decoded))
      self.assertEqual(repr(tritagger), repr(decoded.backoff))
      self.assertEqual(repr(bitagger), repr(decoded.backoff.backoff))
      self.assertEqual(
          repr(unitagger), repr(decoded.backoff.backoff.backoff)
      )
      self.assertEqual(
          repr(self.default_tagger),
          repr(decoded.backoff.backoff.backoff.backoff),
      )
  
file_path: nltk/nltk/test/unit/test_json_serialization.py
imports: import unittest
  from nltk.corpus import brown
  from nltk.jsontags import JSONTaggedDecoder, JSONTaggedEncoder
  from nltk.tag import AffixTagger, BigramTagger, BrillTagger, BrillTaggerTrainer, DefaultTagger, NgramTagger, PerceptronTagger, RegexpTagger, TrigramTagger, UnigramTagger
  from nltk.tag.brill import nltkdemo18
label_desc: Use image node_id 5 for calling the TestJSONSerialization obj's underlying member method code with example usage: obj.test_ngram_taggers() without return types