code: def set_tier(self, tier):
          'Updates the tier and ending tier'
          self.tier = tier
          if tier > self.ending_tier:
              self.ending_tier = tief set_tier(self, tier):
          'Updates the tier and ending tier'
          self.tier = tier
          if tier > self.ending_tier:
              self.ending_tier = tier
docs: Updates the tier and ending tier