How to get sum of fields of Django objects?

Question

Django

There are User and Post models. A user can create a bunch of posts, these posts have a number of likes. How to get the sum of likes from this user from all posts without queriset cycles?
user:

class User(models.Model):
    django_user = models.OneToOneField(
        DjangoUser, on_delete=models.CASCADE, related_name='user')
    name = models.CharField(verbose_name='Имя', max_length=100)
    surname = models.CharField(
        verbose_name='Фамилия', max_length=100)
    phone = models.CharField(
        verbose_name='Телефон', blank=True, max_length=100)
    save_date = models.DateTimeField(
        verbose_name="Дата последнего сохранения", default=now)

    def __str__(self):
        return self.name + ' ' + self.surname

    def get_like_total(self):
        .....

Post

class Post(models.Model):
    active = models.BooleanField(verbose_name='Активность', default=True)
    user = models.ForeignKey(
        'User', verbose_name='Пользователь',
        null=True, related_name='posts', on_delete=models.CASCADE)
    title = models.CharField(
        verbose_name='Заголовок', null=True, max_length=200)
    category = models.ForeignKey(
        'Category', verbose_name='Категория', null=True,
        related_name='posts', on_delete=models.SET_NULL)
    edit_date = models.DateTimeField(
        verbose_name="Дата редактирования", default=now)

PostLike

class PostLikes(models.Model):
    user = models.ForeignKey(
        'User', verbose_name="Пользователь",
        on_delete=models.CASCADE, related_name="likes")
    post = models.ForeignKey(
        'Post', verbose_name="Пост",
        on_delete=models.CASCADE, related_name="likes")

Answer 1

likes = user.posts.all().aggregate(Count('likes'))['likes__count']