Django how to get days count of month in specific year

Question

class MainYear(models.Model):
    year = models.CharField(max_length=4,blank=True,null=True,default=get_current_year())
    def __str__(self):
        return str(self.year)

    @property
    def get_all_month(self):
        return self.MainMonth.all()

    def get_absolute_url(self):
        return reverse("agenda:ajax_month", kwargs={"pk": self.id})
   
class MainMonth(models.Model):
    main_year = models.ForeignKey(MainYear,on_delete=models.CASCADE,blank=True,null=True,related_name="MainYear")
    month = models.PositiveSmallIntegerField (validators=[MaxValueValidator(12)],default=1,blank=True,null=True)
    day_count =  models.PositiveSmallIntegerField (validators=[MaxValueValidator(31)],blank=True,null=True)

    def __str__(self):
        return str(self.month)
    
    @property
    def get_day_count(self):
        # year = self.__main_year.year()
        year = self.objects.all().filter(main_year__MainYear_year='MainYear_year')
        for y in year:
            yea_to_days = self.year  # You already have it
            days_count = monthrange(int(yea_to_days),int(self.month))[1]
            self.day_count = days_count
        return self.day_count

My problem is i want if i select year like 2024 it should be in February 29 days how to make it

i will be save it auto by using save method

django python year month days