class SaleOrder(models.Model):

    _inherit = "sale.order"

    ...

    picking_state = fields.Selection(string="Picking State", related="picking_id.state")

    # this are a states from "stock.picking" model

    warehouse_id = fields.Many2one(

        'stock.warehouse', string='Warehouse',

        required=True, states={'draft': [('readonly', False)], 'sent': [('readonly', False)]},

        default=_default_warehouse_id)

# at the moment the "readonly" of warehouse_id depends on states from "sale.order"

How to include condition:   readonly=True   when     picking_state == "done"  ?