inlineformset_factory explication, svp?

Bonjour

je débute dans la prise en main de django.
Il y a pas mal de doc, meme en anglais, c'est assez compréhensible mais je ne voudrais pas faire d'erreur.
notamment sur cette partie " inline formset" :
est ce que l'on peut m'expliquer a quoi sert : inlineformset_factory

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Inline formsets is a small abstraction layer on top of model formsets. These simplify the case of working with related objects via a foreign key. Suppose you have these two models:
 
class Author(models.Model):
    name = models.CharField(max_length=100)
 
class Book(models.Model):
    author = models.ForeignKey(Author)
    title = models.CharField(max_length=100)
 
If you want to create a formset that allows you to edit books belonging to a particular author, you could do this:
 
>>> from django.forms.models import inlineformset_factory
>>> BookFormSet = inlineformset_factory(Author, Book)
>>> author = Author.objects.get(name=u'Mike Royko')
>>> formset = BookFormSet(instance=author)

merci d'avance

fabien