Use __str__ children classes methods when calling parent class

I've some classes like these :

class Event(models.Model):
    beginning = models.fields.DateTimeField(null=False, blank=True, default=date.today)
    end = models.fields.DateTimeField(null=False, blank=True, default=date.today)

class Festival(models.Model):
    name = models.fields.CharField(max_length=100, blank=True)
    def __str__(self) -> str:
        return f"{self.name}"

class FestivalEdition(Event):
    type = "festival_edition"
    father_festival = models.ForeignKey(Festival, default="", on_delete=models.CASCADE, related_name="edition")    
    def __str__(self) -> str:
        return f"{self.festival_name} {self.year}"

As you can see, only the children classes have their __str__ methods. When I use Event (by the admin interface or by shell), the name is like this <Event: Event object (1)>.

How can I use the __str__ methods of the children (and children of children) classes when calling the parent class ?

I've read the official documentation of Django about inheritance and this post.

I tried this :

class Event(models.Model):

    objects2 = InheritanceManager()

    # The __str__ of Event call the __str__ of children models
    def __str__(self) -> str:        
        event_name = Event.objects2.filter(pk=self.pk).select_subclasses()[0].__str__()        
        return f"{event_name}"    

It works well but only with the children but not the children of the children because I get this recursion Error in this case : RecursionError: maximum recursion depth exceeded while calling a Python object.

source https://stackoverflow.com/questions/75715719/use-str-children-classes-methods-when-calling-parent-class