Coworking/coworking_event/views/res_partner_views.xml

<?xml version="1.0" encoding="utf-8"?>

<odoo>
<!-- Form -->
  <record id="view_form_res_partner" model="ir.ui.view">
    <field name="name">Res_partner Form</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="Events" name="Events">
          <group name="events">
            <field name="manager_event_ids"
              context="{'default_manager_id': active_id}" />
            <field name="event_ids" />
            <field name="events_coworker_count" />
          </group>
        </page>
      </notebook>
    </field>
  </record>
</odoo>