docs: def prev(self):
          """Fetch a set of items with IDs greater than current set."""
          if self.limit and self.limit == self.num_tweets:
              raise StopIteration
  
          self.index -= 1
          if self.index < 0:
              # There's no way to fetch a set of tweets directly 'above' the
              # current set
              raise StopIteration
  
          data = self.results[self.index]
          self.max_id = self.model_results[self.index].max_id
          self.num_tweets += 1
          return data