`save(cascade=True)` doesn't work with `DynamicDocument` without fields?

from mongoengine import *
connect('naruto')


class User(DynamicDocument):
    pass

class Address(DynamicDocument):
    pass

if __name__ == '__main__':
    User.drop_collection()
    Address.drop_collection()

    address = Address()
    address.village = 'Konohagakure'

    # address.save()  # I don't want to have to do this

    naruto = User()
    naruto.name = 'Uzumaki Naruto'
    naruto.title = '7th Hokage'
    naruto.address = address

    # naruto.cascade_save()
    naruto.save(cascade=True)

Doing the above results in mongoengine.errors.OperationError: Only saved documents can have a valid dbref

naruto.cascade_save() succeeds but doesn't save anything.

I don't want to do an object.save() for every new object that get's created. Some of my objects can create new objects on a method call, and I only wish to do a collection.save() once all the objects have been created.

Additionally, I'm looking for complete schema-lessness, so everything is a DynamicDocument with no fields defined.

Is there any way of accomplishing this?

Start by reproducing the example with DynamicDocument, then trace the save(cascade=True) and cascade_save entry points around the unsaved address and its DBRef error. Done means a single save can persist newly created schema-less related objects without requiring each object to be saved first, with regression coverage for this example.