I want to make address fields(street, city, state, zip) required, I used the following 3 type of codes but none of them work for me 

1) <field name="zip" placeholder="ZIP" required="1"/>

2) <field name="zip" placeholder="ZIP" use="required" />

3) <field name="zip" placeholder="ZIP" use="required"><attribute name="required">True</attribute></field>

Source Code

<group>
    <field name="parent_id" invisible="1"/>
    <field name="seller" invisible="1"/>
    <group>
        <label for="street" string="Address"/>
        <div>
            <field name="street" placeholder="Street"/>
            <field name="street2"/>
            <div class="address_format">
                <field name="city" placeholder="City"/>
                <field name="state_id" class="oe_no_button" placeholder="State" options="{"no_open": True, "no_create": True}"/>
                <field name="zip" placeholder="ZIP"/>
            </div>
            <field name="country_id" placeholder="Country" class="oe_no_button" options="{"no_open": True, "no_create": True}"/>
        </div>
        <field name="website" widget="url" placeholder="e.g. www.odoo.com"/>
    </group>
    <group>
        <field name="phone" placeholder="e.g. +32.81.81.37.00"/>
        <field name="mobile"/>
        <field name="user_ids" invisible="1"/>
        <field name="email" widget="email" attrs="{'required': [('user_ids','!=', [])]}" readonly="1"/>
        <field name="title" options="{"no_open": True,"no_create": True}"/>
    </group>
</group>