code: def sort_by_decreasing_count(self):
          
          words = [w for w, ct in self._counts.most_common()]
          v = self.subset(words)
          return v
docs: Return a **new** `Vocab` object that is ordered by decreasing count.
  
          The word at index 1 will be most common, the word at index 2 will be
          next most common, and so on.
  
          :return: A new vocabulary sorted by decreasing count.
  
          NOTE: UNK will remain at index 0, regardless of its frequency.