How to initialize Django nested inline formset with dictionary

I have following declaration of inline Formset:

ModelAFormSet = generic_inlineformset_factory(
    ModelA,
    form=AddModelAForm,
    formset=BaseModelAFormset,
    min_num=1,
    extra=0)

ModelA looks as follows:

class ModelA(models.Model):
   name = models.CharField(max_length=100)
   description = models.CharField(max_length=100)

   content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
   object_id = models.PositiveIntegerField()
   model_object = GenericForeignKey('content_type', 'object_id')

and BaseModelAFormset is defined in following way:

class BaseModelAFormset(BaseGenericInlineFormSet):

    def add_fields(self, form, index):
        super(BaseModelAFormset, self).add_fields(form, index)

        form.nested = ModelBFormset(
            instance=form.instance,
            data=form.data if form.is_bound else None,
            files=form.files if form.is_bound else None,
            prefix='%s-%s' % ( 
                form.prefix,
                ModelBFormset.get_default_prefix()),
        )

The I have ModelBFormset defined as follows:

ModelBFormset = inlineformset_factory(ModelA,
                                      ModelB,
                                      form=AddModelBForm,
                                      extra=1)

with ModelB looking like this:

class ModelB(models.Model):
    quantity = models.IntegerField()
    value = models.DecimalField(max_digits=7, decimal_places=2)
    model_a = models.ForeignKey(
        ModelA,
        on_delete=models.CASCADE,
        related_name='model_as'
    )

I know I can initialize ModelAFormSet following way:

init_list = []
for my_model in self.edit_parent.my_models.all():
   dictionary = { 
     'name': my_model.name,
     'description': my_model.description,
     'id': my_model.id}
   init_list.append(dictionary)

formset = ModelAFormSet(initial=init_list)

But I have no clue how I could also initialize here ModelBFormset. Is there any special field name I should pas as a key to initial dictionary?