How can I add custom fields to inherited Models and views when I Tried to add it is throwing an Parse Error solve this

ParseError: "Error while validating constraint

Field `district` does not exist

Error context:
View `res.partner`
[view_id: 1094, xml_id: n/a, model: res.partner, parent_id: 124]
None" while parsing file:///c:/program files (x86)/odoo 10.0/server/odoo/addons/localizationindonesia/views/partner.xml:4, near
<record id="add_new_partner" model="ir.ui.view">
            <field name="name">res.partner</field>
            <field name="model">res.partner</field>
            <field name="inherit_id" ref="base.view_partner_form"/>
            <field name="arch" type="xml">
              <field name="country_id" position="after">
                <field name="district" placeholder="District"/>
              </field>
            </field>
    </record>

I tried to add like this

In Model

class ResPartner(models.Model):


    _name = 'res.partner'

    _inherit = 'res.partner'

    district = fields.Char(string='district', Size=32)

In Xml:

<record id="add_new_partner" model="ir.ui.view">
            <field name="name">res.partner</field>
            <field name="model">res.partner</field>
            <field name="inherit_id" ref="base.view_partner_form"/>
            <field name="arch" type="xml">
              <xpath expr="//field[@name='country_id']" position="after">
                <field name="district" placeholder="district"/>
              <xpath/>
            </field>
    </record>