if self.CalculatePriorityValue(NowKey) > self.CalculatePriorityValue(NextKey):
                                            if Options.get((self.BuildRuleFamily, NextKey)) != None:  
                                                Options.pop((self.BuildRuleFamily, NextKey))
                                        else:
                                            if Options.get((self.BuildRuleFamily, NowKey)) != None: