Upsert on bulk insert

I want to upsert on bulk insert.

Here is my code snippets.

from datetime import datetime
from mongoengine import *


connect('test')


class Exclusions(Document):
    user_id = LongField(required=True)
    target_user_id = LongField(required=True)
    category = StringField(required=True)
    created_at = DateTimeField(default=datetime.now().replace(microsecond=0))

    meta = {
        'index_background': True,
        'indexes': [
            {
                'fields': ['+user_id'],
            },
            {
                'fields': ('user_id', 'target_user_id'),
                'unique': True
            }
        ]
    }


current_time = datetime.now().replace(microsecond=0)
ex1 = Exclusions(user_id=1, target_user_id=2, category='likes', created_at=current_time)
ex2 = Exclusions(user_id=3, target_user_id=4, category='likes', created_at=current_time)
go = []
go.append(ex1)
go.append(ex2)

Exclusions.objects.insert(go)

If I execute twice, it throw errors.

pymongo.errors.BulkWriteError: batch op errors occurred

mongoengine.errors.NotUniqueError: Document must not have _id value before bulk write (batch op errors occurred)

I know it is because of index. But I want to insert if it doesn't exist and update if it exists on bulk insert method.

Is there any options for it?

Start at the Exclusions.objects.insert(go) entry point and trace MongoEngine's bulk-insert handling into the PyMongo bulk-write behavior. Define how repeated inserts should update documents matching the unique user_id and target_user_id pair, then verify that duplicates no longer produce the reported errors.