score_fn=BigramAssocMeasures.chi_sq
n=200
bigram_finder = BigramCollocationFinder.from_words(all_words)
bigrams = bigram_finder.nbest(score_fn, n)

Traceback (most recent call last):
  File "C:/Users/HeeswiM/Desktop/Scriptie/CorpusBasisWERKT.py", line 98, in <module>
    evaluate_classifier(best_bigram_word_feats)
  File "C:/Users/HeeswiM/Desktop/Scriptie/CorpusBasisWERKT.py", line 21, in evaluate_classifier
    negfeats = [(featx(movie_reviews.words(fileids=[f])), 'neg') for f in negids]
  File "C:/Users/HeeswiM/Desktop/Scriptie/CorpusBasisWERKT.py", line 92, in best_bigram_word_feats
    bigrams = bigram_finder.nbest(score_fn, n)
  File "C:UsersHeeswiMAppDataRoamingPythonPython27site-packagesnltkcollocations.py", line 112, in nbest
    return [p for p, s in self.score_ngrams(score_fn)[:n]]
  File "C:UsersHeeswiMAppDataRoamingPythonPython27site-packagesnltkcollocations.py", line 108, in score_ngrams
    return sorted(self._score_ngrams(score_fn), key=lambda t: (-t[1], t[0]))
  File "C:UsersHeeswiMAppDataRoamingPythonPython27site-packagesnltkcollocations.py", line 100, in _score_ngrams
    score = self.score_ngram(score_fn, *tup)
  File "C:UsersHeeswiMAppDataRoamingPythonPython27site-packagesnltkcollocations.py", line 169, in score_ngram
    return score_fn(n_ii, (n_ix, n_xi), n_all)
  File "C:UsersHeeswiMAppDataRoamingPythonPython27site-packagesnltkmetricsassociation.py", line 220, in chi_sq
    return n_xx * cls.phi_sq(n_ii, (n_ix, n_xi), n_xx)
  File "C:UsersHeeswiMAppDataRoamingPythonPython27site-packagesnltkmetricsassociation.py", line 212, in phi_sq
    ((n_ii + n_io) * (n_ii + n_oi) * (n_io + n_oo) * (n_oi + n_oo)))
ZeroDivisionError: float division by zero