Mongoengine - save only one embedded document

I have a MongoDB document that is quite large, so it takes a few seconds to save. One of the fields is a list of embedded documents. When I update one of the items in the list, and I want to save to the database, I want to be able to save just the specific embedded document instead of the entire document.

An abbreviated part of my code is as follows:

class Paragraph(mongoengine.EmbeddedDocument):
    _id = mongoengine.ObjectIdField(required=True, default=lambda: ObjectId())
    text = mongoengine.StringField()
    updated = mongoengine.BooleanField()

class Contract(mongoengine.Document):
    paragraphs = mongoengine.ListField(mongoengine.EmbeddedDocumentField(Paragraph))

    def save(self, **kwargs):
        if kwargs.get('update_only', False):
            super(Contract, self).update(set__paragraphs=self.paragraphs)
        else:
            super(Contract, self).save(**kwargs)

So this code allows me to save only the paragraphs field in the Contract document, which is already a lot more efficient than saving the entire document. However, this still takes a while, as there are a lot of paragraphs in a document.

I added the attribute updated to Paragraph. I want to be able to save only those paragraphs that are marked as updated.

I found a way to do this by first removing all updated paragraphs from the database and then adding new ones.

Contract.objects(id=id).update_one(pull__paragraphs={'_id': id_of_updated_paragraph})
Contract.objects(id=id).update_one(add_to_set__paragraphs=updated_paragraph)

This still feels like very inefficient. Is there a better way to do this?