I get this error and I don't know how to fix it:

odoo.tools.convert.ParseError: while parsing /mnt/extra-addons/packing_operation/views/packing_order_views.xml:4, somewhere inside
<record id="view_packing_order_tree" model="ir.ui.view">
    <field name="name">packing.order.tree</field>
    <field name="model">packing.order</field>
    <field name="arch" type="xml">
        <tree>
            <field name="name"/>
            <field name="state" widget="badge" options="{'style': 'color'}"/>
            <field name="user_id"/>
            <field name="full_packing_date"/>
        </tree>
    </field>
    </record>

ChatGPT thinks that tree is OK for ir.ui.view.type.

My model:

class PackingOrder(models.Model):

    _name = "packing.order"

    _description = "Packing Order"

    name = fields.Char(string="Task number",

                       required=True,

                       copy=False,

                       default="New",

    )

    user_id = fields.Many2one("res.users", string="Operator")

    cancellation_reason = fields.Text(string="Cancel reason")

    line_ids = fields.One2many("packing.order.line",

                               "order_id",

                               string="Order lines",

                               )

    full_packing_date = fields.Datetime(

        string="Date of full packing", readonly=True

    )

    barcode_scanner = fields.Char(string="Scanner (product ID)")

    state = fields.Selection([

    ('waiting', 'Waiting'),

    ('in_progress', 'In progress'),

    ('done', 'Done'),

    ('cancel', 'Cancel'),

    ], string="Status", compute='_compute_state', store=True)