How can I add a new field named partner_id_shipping to the account_invoice. It is the same like partner_id but with an other name.

How Can I implement this with a new modul?

I try this:

from import openerp.osv fields, osv


class account_invoice(osv.osv):
    _inherit = 'account.invoice'

    _columns = {
        
'partner_id_shipping': fields.Many2one(, string='Partner', change_default=True,
required=True, readonly=True, states={'draft''readonly': [(, False)]},
track_visibility='always'),
}