@staticmethod
def save(lexicon, out_f):
    """ Saves the word detection result in a csv file.
        """
    words = sorted(lexicon, key=lambda x: (len(x), -lexicon[x][0], -lexicon
        [x][1], -lexicon[x][2], -lexicon[x][3]))
    with open(out_f, 'w') as f:
        f.write('Word,Frequency,PMI,R_Entropy,L_Entropy\n')
        for word in words:
            f.write('{},{},{},{},{}\n'.format(word, lexicon[word][0],
                lexicon[word][1], lexicon[word][2], lexicon[word][3]))
