I'm trying to create dellivery orders based on warehouses selected 
i created a function on sale order to create multi delivery orders , but delivery orders not found
This is the code:

import random
from odoo import models , fields,api,_
class SaleOrder(models.Model):
    _name='sale.order'
    _inherit = 'sale.order'
    warehouse_ids = fields.Many2many('stock.warehouse', string='Warehouses')

    @api.model
    def create(self, vals):
        res = super(SaleOrder, self).create(vals)
        for line in res.order_line.warehouse_ids:

            for w in line:
                picking_vals = {
                    'partner_id': res.partner_shipping_id.id,
                    'location_id': w.lot_stock_id.id,
                    'location_dest_id': res.partner_shipping_id.property_stock_customer.id,
                    'picking_type_id':random.randint(1,6),
                }
                self.env['stock.picking'].create(picking_vals)
                print(picking_vals)
        return res
class SaleOrderLine(models.Model):
   _inherit = 'sale.order.line'

   warehouse_ids = fields.Many2many('stock.warehouse',string="Warehouses ")

class ProductTemplate(models.Model):
   _inherit = 'product.template'
   warehouse_id = fields.Many2one('stock.warehouse',string="Warehouse ")


class ProductProduct(models.Model):
   _inherit = 'product.product'
   warehouse_id = fields.Many2one('stock.warehouse',string="Warehouse ")

it is not exist:

only one delivery and i select two warehouses: