code: def normalize_ranking(ranking_tuples):
          
          ranking_tuples = sorted(ranking_tuples, key=lambda x: x[1])
          normalized = [(ranking_tuples.pop(0)[0], 0)]
          while ranking_tuples:
              current = ranking_tuples.pop(0)
              normalized.append((
                  current[0],
                  normalized[-1][1] if current[1] == normalized[-1][1] \
                      else normalized[-1][1] + 1,
                  ))
          return normalized
docs: Normalize rankings by reducing them to the simplest
          order.  E.g.:
              If the rankings for 2 choices are -244 and 4,
              this function will normalize them to 0 and 1,
              respectively.
          Parameters:     ranking_tuples should be an iterable
                              of tuples of form (choice, ranking)
          Return a list of tuples of form (choice, ranking), with
          the ranking normalized.