python - How to change record of object in Django's model instantly? -

i have class , objects, want when save new record, django checks if "is_it_true" false or true, if true change default value of "number" new value corresponded count of objects have "is_it_question" plus one; , if false, default of "number" remain defaut(100). should do?

class typefourchoice(models.model):     question_choice = models.foreignkey(typefour)     is_it_question = models.booleanfield(default=false)     number = models.positiveintegerfield(blank=false, default=100)     word_or_words = models.charfield(default='', blank=false, max_length=20)     timestamp = models.datetimefield(auto_now_add=true)      def __str__(self):         return "{}".format(self.question_choice)      @classmethod     def save(cls, *args, **kwargs):         no = cls.objects.exclude(number=100).count()         if no none:             pass         else:             clss = cls.objects.get(???????)             if clss.is_it_question:                 no += 1                 clss.number = no                 clss.save(*args, **kwargs)             else:                 clss.number = 100                 clss.save(*args, **kwargs) 

you should remove @classmethod decorator save() method. , simplify method this:

def save(self, *args, **kwargs):     # new objects have no `pk`     if self.pk none , self.is_it_question:         self.number = typefourchoice.objects.filter(is_it_question=true) \                                             .count() + 1     super(typefourchoice, self).save(*args, **kwargs)