Word Frequency calculation in a phrase list might be wrong

[vertika-19]

You are calculating frequency distribution of words from Phrase list.
Phrase list is a set, so a word will be present just once in it. Using Counter(chain.from_iterable(phrase_list)) to find freq_distribution will only take care of the words in a set, which I think is wrong.
Candidate keywords which might occur many times in the text will be there just once in the phrase list.