How to make it so that when saving data in the database, the data generated by the function is automatically inserted into the field Django ORM

I’m writing a site on Django and ran into a problem

I have a title field in the database, which stores the title of the book, but I want to add a chunk_title field, which will store the title of the book, divided into chunks of 3 characters, I wrote a method that does this, but I need that when inserted into the database, it was automatically applied and its result was inserted into chunk_title

This is my DB model,where the last field is the field I want to auto-generate the value into:

class Book(models.Model):
    """
    Клас,який зберігає всі книги на сайті
    """

    title = models.CharField(max_length=120, default=' ', verbose_name='Назва')
    description = models.TextField(verbose_name='Опис')
    category = models.ForeignKey(Category, on_delete=models.CASCADE, verbose_name='Категорія')
    date_at = models.DateField(auto_now_add=True, verbose_name='Дата створення')
    image = models.ImageField(upload_to='photos/%Y/%m/%d/')
    authors = models.ManyToManyField(Author, verbose_name='Автори')
    content = models.FileField(upload_to='contents/%Y/%m/%d/', blank=True)
    price = models.IntegerField(verbose_name='Ціна', default='0')
    chunk_title_book = models.TextField(default=' ')

And this is my method, the result of which I want to insert into that field (it is in the same class, i.e. Book):

    def chunk_title(self, string: str) -> str:
        """
        Розбиває назву книги на чанки по 3 символи макисмум для подальшого пошуку по цих чанках
        """
        chunk_string = ' '.join(textwrap.wrap(string, 3))
        return chunk_string + ' ' + ' '.join(string.split())

Does anyone know if this is possible to implement, and if yes, how?

>Solution :

You need to overwrite the save method of django Model, and assign the value of chunk_title_book by calling the function:

class Book(models.Model):
    """
    Клас,який зберігає всі книги на сайті
    """
    .
    .
    .
    .
    def save(self, *args, **kwargs):
        # overwriting `chunk_title_book` attribute 
        # Assumes chunk_title function is Book class's method
        self.chunk_title_book = self.chunk_title(self.title)
        super(Book, self).save(*args, **kwargs)