odoo-event-addons/event_question_sale/models/event_question_answer.py

from odoo import api, fields, models, _


class EventQuestionAnswer(models.Model):
    _inherit = "event.question.answer"

    extra_product_ids = fields.One2many(
        comodel_name="event.question.answer.product",
        inverse_name="answer_id",
        string="Extra Products",
        help="These producs will be added to the sale order of the booking with the given quantity and price.",
    )