@staticmethod
def __updateMany(cls_or_instance, query: dict, update: dict, upsert=False,
    array_filters=None, bypass_document_validation=False, collation=None,
    session=None, db=None):
    """Update specific fields for many documents.

        equal to db.collection.updateMany(query, {$set: {key: new_val})
        """
    __db = db if db else cls_or_instance.__db
    return __db[cls_or_instance.__collection__].update_many(query, {'$set':
        update}, upsert=upsert, array_filters=array_filters,
        bypass_document_validation=bypass_document_validation, collation=
        collation, session=session)
