AVCaptureSession-addInput.swift

let availableDevices = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .back).devices

do {
    if let captureDevice = availableDevices.first {
        captureSession.addInput(try AVCaptureDeviceInput(device: captureDevice))
    }
} catch {
    print(error.localizedDescription)
}