How to check if bluetooth is enabled

viewDidLoad:

self.cbCentralManager = CBCentralManager(delegate: self, queue: nil, options: [CBCentralManagerOptionShowPowerAlertKey : false])
self.cbCentralManager.delegate = self

handle:

    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        switch central.state {
        case .poweredOn:
            btEnabled = true
            break
        case .poweredOff:
            btEnabled = false
            break
        case .resetting:
            break
        case .unauthorized:
            break
        case .unsupported:
            break
        case .unknown:
            break
        default:
            break
        }
    }

Protocol:

extension MyVC: CBCentralManagerDelegate {
}