code: def augment_with_ngrams(unigrams, unigram_vocab_size, n_buckets, n=2):
      
  
      def get_ngrams(n):
          return list(zip(*[unigrams[i:] for i in range(n)]))
  
      def hash_ngram(ngram):
          bytes_ = array.array('L', ngram).tobytes()
          hash_ = int(hashlib.sha256(bytes_).hexdigest(), 16)
          return unigram_vocab_size + hash_ % n_buckets
  
      return unigrams + [hash_ngram(ngram) for i in range(2, n + 1) for ngram in get_ngrams(i)]
docs: Augment unigram features with hashed n-gram features.