input: Write a python function to determine the highest total score from a list of tuples.
  assert highest_total_score([('Juan Whelan',90),('Sabah Colley',88),('Peter Nichols',7),('Juan Whelan',122),('Sabah Colley',84)])==('Juan Whelan', 212)
  assert highest_total_score([('Juan Whelan',50),('Sabah Colley',48),('Peter Nichols',37),('Juan Whelan',22),('Sabah Colley',14)])==('Juan Whelan', 72)
  assert highest_total_score([('Juan Whelan',10),('Sabah Colley',20),('Peter Nichols',30),('Juan Whelan',40),('Sabah Colley',50)])==('Sabah Colley', 70)
output: def highest_total_score(scores):
      score_dict = {}
      for name, score in scores:
          if name in score_dict:
              score_dict[name] += score
          else:
              score_dict[name] = score
      return max(score_dict.items(), key=lambda x: x[1])