1. Define your list view:

<record id="tree_all_customers" model="ir.ui.view"> 
    <field name="model">res.partner</field> 
    <field name="arch" type="xml"> 
        <tree decoration-bf="customer"
              decoration-danger="supplier"
              decoration-warning="customer and supplier"> 
            <field name="name" /> 
            <field name="customer" invisible="1" /> 
            <field name="supplier" invisible="1" /> 
        </tree> 
    </field> 
</record> 

2. Register a tree view in the action we created in the Adding a menu item and window action recipe of this chapter:

<record id="action_all_customers_tree" 
        model="ir.actions.act_window.view"> 
    <field name="act_window_id" ref="action_all_customers" /> 
    <field name="view_id" ref="tree_all_customers" />
    <field name="view_mode">tree</field> 
    <field name="sequence">5</field>
</record>