Hi,

Please refer to the code:

<odoo>

    <data>

        <record id="crm_lead_access_by_self_and_supervisor" model="ir.rule">

            <field name="name">Lead (CRM) access by self, supervisor, or unassigned</field>

            <field name="model_id" ref="crm.model_crm_lead"/>

            <field name="domain_force">

                ["|", "|",

                    ("user_id", "=", user.id),

                    ("user_id", "=", False),

                    ("user_id.parent_id", "=", user.id)

                ]

            </field>

            <field name="groups" eval="[(4, ref('base.group_user'))]"/>

            <field name="perm_read" eval="True"/>

            <field name="perm_write" eval="True"/>

            <field name="perm_create" eval="True"/>

            <field name="perm_unlink" eval="False"/>

        </record>

    </data>

</odoo>

- Use crm.model_crm_lead instead of crm.lead.

- Changed perm_unlink to False to prevent accidental deletion of leads.

- Replaced user_id.user_ids.supervisor (complex and error-prone) with user_id.parent_id (common way to define supervisor in Odoo hierarchy).

Hope it helps.