) {
                let selector = this.$.machineSelector
                if (selector.value) {
                    // if found duplicate it will return index > -1
                    let isDuplicated = this.machines.map(item => item.number).indexOf(selector.selectedItem.number) > -1
                    if (this.machines.length < this.stationMaxMachine) {
                        if (isDuplicated) {
                            this.toastText = 'notification-already-added-this-machine'
                       