Hello, 

Im actually try to make my first custom module. 

But i cant understand where i made an mistake. If someone can give a hand for this. 

Thank you

<?xml version="1.0" encoding="UTF-8"?>
<odoo>
  <record id="sale_order_form_view_inherit" model="ir.ui.view">
    <field name="name">sale.order.form.view.inherit</field>
    <field name="model">sale.order</field>
    <field name="inherit_id" ref="sale.view_order_form"/>
    <field name="arch" type="xml">
      <xpath expr="//header/field[@name='state']" position="replace">
        <field name="state" widget="statusbar" statusbar_visible="draft,sent,waiting,sale"/>
      </xpath>
      <xpath expr="//header" position="inside">
        <button name="action_payment_receive" type="object" string="Confirm Payment"
                attrs="{'invisible': [('state', '!=', 'waiting')]}"/>
      </xpath>
    </field>
  </record>
</odoo>