查询类：

class Trace():    def Lookup(self):        #查询其子类设置的内容        self.HeadFormat = "%-*s%*s"        self.Bwidth = len(self.Booktime);self.Awidth = len(self.Arrivetime)        self.Swidth = len(self.Status);self.Lwidth = len(self.Location)        self.Hwidth = self.Bwidth + self.Awidth + self.Swidth + self.Lwidth        self.Hvar = self.Hwidth + 10                print self.Hvar * '-'        print self.HeadFormat % (4,'Item',self.Hvar-4,'Info')        print self.Hvar * '='        print self.HeadFormat % (8,'Booktime:',self.Hvar-8,self.Booktime)        print self.HeadFormat % (10,'Arrivetime:',self.Hvar-10,self.Arrivetime)        print self.HeadFormat % (6,'Status:',self.Hvar-6,self.Status)        print self.HeadFormat % (8,'Location:',self.Hvar-8,self.Location)        print self.Hvar * '-'

class Set(Trace):    def SetVar(self):         #设置相关信息        self.Booktime = str(raw_input("Please input the Booktime:"))               self.Arrivetime = str(raw_input("Please input the Arrivetime:"))        self.Status = str(raw_input("Please input the Status:"))        self.Location = str(raw_input("Please input the Location:"))