tensorflow - ValueError: too many values to unpack (expected 4) -

i getting "valueerror: many values unpack (expected 4)" below code. please me!! trying lemmatize , cut off common words , add library can identify common words , find relationship between words.

def build_dataset(words, vocabulary_size):     lexicon = []     l in words:          all_words = word_tokenize(l.lower())         lexicon += list(all_words )     lexicon = [lemmatizer.lemmatize(i) in lexicon]      w_counts = counter(lexicon)      word = []      w in w_counts:         if 5000 > w_counts[w] > 50 :             word.append(w)      print(len(word))     return word      count = [['unk', -1]]     count.extend(collections.counter(word).most_common(vocabulary_size - 1))     dictionary = dict()     l2, _ in count:         dictionary[l2] = len(dictionary)         data = list()         unk_count = 0     l2 in word:         if l2 in dictionary:             index = dictionary[l2]         else:             index = 0              unk_count += 1             data.append(index)             count[0][1] = unk_count             reverse_dictionary = dict(zip(dictionary.values(), dictionary.keys()))          return data, count, dictionary, reverse_dictionary      data, count, dictionary, reverse_dictionary = build_dataset(words, vocabulary_size)