odoo12-重写源码方法解决税率无法带出问题

-场景： 报价单直接转采购单，出现报价单明细行的税率无法带出到采购订单明细行

    def re_purchase(self):
        view_id = self.env.ref('purchase.purchase_order_form').id
        info_line = self.info_line_ids
        record = []
        for index, line in enumerate(info_line):
            default = {
                'xhseq': index + 1,
                'product_id': line.product_id.id,
                'product_qty': line.product_qty,
                'product_uom': line.uom_id.id,
                'lprice_tax': line.price_unit_tax,
                'taxes_id': line.tax_id.id,
                'remark': line.remark,
                'price_total': line.amount_total,
                'date_planned': self.sale_date if self.sale_date else fields.Date.today(),
                'name': 'test'
            }
            record.append(default)
        return {
            'type': 'ir.actions.act_window',
            'view_type': 'form',
            'view_mode': 'form',
            'res_model': 'purchase.order',
            'views': [(view_id, 'form')],
            'target': 'self',
            'context': {
                'default_order_line': record,
                'skip_change': 1
            }
        }

    # 注释订单行税率自动获取问题
    @api.onchange('fiscal_position_id')
    def _compute_tax_id(self):
        context = self._context
        skip = context.get('skip_change', False)
        if not skip:
            return super(PurchaseOrder, self)._compute_tax_id()
        else:
            pass