from odoo import api, fields, models, _


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

    @api.onchange('sale_ok')
    def _onchange_sale_ok(self):
        """ Maintains the value of `available_in_pos` when unchecking `sale_ok`,
            by storing its value before calling parent's method,
            then assigning the stored value.
        """
        was_available = self.available_in_pos
        super(ProductTemplate, self)._onchange_sale_ok()
        if not self.sale_ok:
            self.available_in_pos = was_available