contract/product_contract/models/product_template.py

# -*- coding: utf-8 -*-
# Copyright 2017 LasLabs Inc.
# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).

from odoo import api, fields, models


class ProductTemplate(models.Model):
    _inherit = 'product.template'

    is_contract = fields.Boolean('Is a contract')
    contract_template_id = fields.Many2one(
        comodel_name='account.analytic.contract',
        string='Contract Template',
    )

    @api.onchange('is_contract')
    def _change_is_contract(self):
        """ Clear the relation to contract_template_id when downgrading
        product from contract
        """
        if not self.is_contract:
            self.contract_template_id = False