code: def _roundSlist(slist):
      
      slist[-1] = 60 if slist[-1] >= 30 else 0
      for i in range(len(slist)-1, 1, -1):
          if slist[i] == 60:
              slist[i] = 0
              slist[i-1] += 1
      return slist[:-1]
docs: Rounds a signed list over the last element and removes it.