How to calculate the average price per room through aggregate?

Question

Django

There are three models

class Hotel(models.Model):
    user = models.ForeignKey(MyUser, on_delete=models.CASCADE, verbose_name='Владелец')
    title = models.CharField(max_length=100, verbose_name='Название')

    def average_price(self):
        return self.number_set.aggregate(Avg('get_price'))

class Number(models.Model):
    hotel = models.ForeignKey(Hotel, default=1, on_delete=models.CASCADE, verbose_name='Отель')
    title = models.CharField(max_length=100, verbose_name='Название')

    def get_price(self):
        return self.numberprice_set.all.aggregate(Avg('price'))

class NumberPrice(models.Model):
    start = models.DateField(verbose_name='Начало периода')
    finish = models.DateField(verbose_name='Конец периода')
    price = models.IntegerField(null=True, blank=True, verbose_name='Цена')
    number = models.ForeignKey(Number, on_delete=models.CASCADE, verbose_name='Номер')

Hotels are displayed in the template, you need to display the average price of rooms in each hotel. I wrote methods in models, but I don’t know how to call the get_price method from the average_price method of the Hotel model. I did not make the price a field in the number model, since the price will depend on the periods (dates).