i have a many2field from a model called related that contains cars and their models which are same in some parts that we are sell in our market we need to make a unique price for each car,model,year not for all as package

actually i don't now what should i do

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

related = fields.Many2many(comodel_name="relate",relation='car', string="",domain="[('item','=', item )]" )


class relate(models.Model):
_name = 'relate'
_rec_name = 'code'

code = fields.Char(string="product Code", required=False, compute=ref , store=True)
strings = fields.Char(string="", required=False, )
item = fields.Many2many(comodel_name="item", string="Items", )
car = fields.Many2one(comodel_name="cars", string="car", required=True, ondelete='restrict', )
model = fields.Many2many(comodel_name="models", string="",domain="[('car','=', car )]" )
start = fields.Char(string="", required=False, )
end = fields.Char(string="", required=False, )
rang = fields.One2many(comodel_name="yearrange", inverse_name="product_id", store=True, string="Years" ,)
ignore = fields.Char(string="Ignore", required=False, )
sum = fields.Char(string="profit sumition", required=False, compute=sum_pro )
total = fields.Integer(string="total of elements", required=False,compute=total )