def refresh(self, cr, uid, ids, context={}):
    conn = cups.Connection()
    printers = conn.getPrinters()
    for r in self.browse(cr, uid, ids, context=context):
        data = printers.get(r.code)
        if not data:
            **raise osv.except_osv(_('Error!'), _('Printer "%s" not found!') % r.code)**
        note = '\n'.join(map(lambda key: "%s: %s" % (key, data[key]), data))
        r.write({'note':note}, context=context)
    return True