Odoo 11 one2many场没有保存

Question

在Odoo v10中，这个on_change方法效果非常好：

@api.onchange("partner_id")
def onchange_partner_id(self):
    self.zapocet_line_pohledavky = False
    self.zapocet_line_zavazky = False

    account_move_line_obj = self.env['account.move.line']
    val = {'value': {'zapocet_line_pohledavky': [], 'zapocet_line_zavazky': []}}
    for statement in self:
            if statement.partner_id:
                domain = [('account_id.user_type_id.type', 'in', ('payable', 'receivable')), ('move_id.state', '=', 'posted'),
                          ('partner_id.id', '=', statement.partner_id.id),]
                line_ids = account_move_line_obj.search(domain, order="date asc")
                for line in line_ids:
                    if line.amount_residual != 0 and line.credit > 0:
                        res = {
                            "move_line_id": line.id,
                        }
                        val['value']['zapocet_line_zavazky'].append(res)

                    if line.amount_residual != 0 and line.debit > 0:
                        qes = {
                            "move_line_id": line.id,

                        }
                        val['value']['zapocet_line_pohledavky'].append(qes)
            self.zapocet_line_pohledavky = val['value']['zapocet_line_pohledavky']
        return val

有没有人知道为什么在v11中它能很好地加载线条，但它们在保存时会消失？