wordbank = {}
for word in article_one:
    word = word.lower().strip(string.punctuation)
if word not in wordbank:
    wordbank[word] = 1
else:
    wordbank[word] += 1
sortedwords = sorted(iter(wordbank.items()), key=operator.itemgetter(1))
for word in sortedwords:
    pass
Поиск наименее общих элементов в списке