i use odoo v10 to do some task but this errior is apearing please can any one help my? : #model.py
# -*- coding: utf-8 -*-

from openerp import models, fields


class fleet_vehicle_direction(models.Model):

    _name = 'fleet.vehicle.direction'
    name = fields.Char(related='vehicle_id.name', string='vehicle name', store=True)
    vehicle_id = fields.Many2one('fleet.vehicle', 'select vehicle name', required=True, help='select vehicle name')
    Quotations_id = fields.One2many('sale.order', 'name', 'Quotation', required=True,help='select  Quotation name')




[enter image description here][1]


#error  when add a new   Quotation
[enter image description here][2]


  [1]: https://i.stack.imgur.com/8oiHG.png
  [2]: https://i.stack.imgur.com/G6Clr.png