Hello,

I try to add this feature:

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


     # Pour chaque iid dans Invoice_IDS

    def _amount_weight(self, cr, uid, ids, name, args, context=None):
        invoice_ids = self.pool.get('account.invoice').search(cr, uid, [])

        total_weight = 0
        for iid in invoice_ids:
            line_ids = self.pool.get('account.invoice.line').search(cr, uid, [('id', '=', iid)], offset=0, limit=None, order=None, context=None, count=False)

            for lid in line_ids:
                i_line = self.pool.get('account.invoice.line').browse(cr, uid, iid, context=context)
                i_weight = i_line.weight
                total_weight = total_weight + i_weight
        return total_weight

    _columns = {
        'weight_tot_test': fields.function(_amount_weight, type='char', string='Poids Total')
    }
account_invoice()

but it returns me this erreure:

AttributeError: 'float' object has no attribute 'get'

Someone has an idea?

THX