I have made the new module followed by the tutorial in odoo documentation. But when I made view inheritance, i have an error like this

ParseError: "Error while validating constraint

Field `session_ids` does not exist

Error context:
View `partner.instructor`
[view_id: 228, xml_id: n/a, model: res.partner, parent_id: 124]
None" while parsing file:///d:/addons/openacademy/views/partner.xml:5, near
<record model="ir.ui.view" id="partner_instructor_form_view">
            <field name="name">partner.instructor</field>
            <field name="model">res.partner</field>
            <field name="inherit_id" ref="base.view_partner_form"/>
            <field name="arch" type="xml">
                <notebook position="inside">
                    <page string="Sessions">
                        <group>
                            <field name="instructor"/>
                            <field name="session_ids"/>
                        </group>
                    </page>
                </notebook>
            </field>
        </record>

I have to import partner in __init__.py and add views/partner.xml in __manifest__.py
Please check the script i have made and tell the error.

partner.py

from odoo import modelds, fields, api

class Partner(models.Model):
    _inherit = 'res.partner'

    # Add a new column to the res.partner model, by default partners are not
    # instructors
    instructor = fields.Boolean("Instructor", default=False)

    session_ids = fields.Many2many('openacademy.session',
        string="Attended Sessions", readonly=True)

partner.xml

<odoo>
    <data>
        <!-- Add instructor field to existing view -->
        <record model="ir.ui.view" id="partner_instructor_form_view">
            <field name="name">partner.instructor</field>
            <field name="model">res.partner</field>
            <field name="inherit_id" ref="base.view_partner_form"/>
            <field name="arch" type="xml">
                <notebook position="inside">
                    <page string="Sessions">
                        <group>
                            <field name="instructor"/>
                            <field name="session_ids"/>
                        </group>
                    </page>
                </notebook>
            </field>
        </record>

        <record model="ir.actions.act_window" id="contact_list_action">
            <field name="name">Contacts</field>
            <field name="res_model">res.partner</field>
            <field name="view_mode">tree,form</field>
        </record>
        <menuitem id="configuration_menu" name="Configuration"
                  parent="main_openacademy_menu"/>
        <menuitem id="contact_menu" name="Contacts"
                  parent="configuration_menu"
                  action="contact_list_action"/>
    </data>
</odoo>

Thank you in advance