how to display many2many relationship data in odoo

Question

First Table

class vehicle_service(models.Model):                                                        
    s_type=fields.Many2many('service.service','service_rel','sid','s_type',string="Service Name", required="1")

Second Table

class service_service(models.Model):

    _name="service.service"


    name=fields.Char("Name")
    cost=fields.Float("Service Cost")