iOS beginSession() error

[rich1812]

Hi, I am new to this swift thing, I study a piece of downloaded code, when I try to run it, it gives me an error,
"Use of unresolved identifier 'beginSession'" at the top of the code, I imported UIKit and imported AVFoundation. is there anything else I need to import? Thanks.
BTW I use xcode 9.4.1.

/ Loop through all the capture devices on this phone
        for device in devices {
            // Make sure this particular device supports video
            if (device.hasMediaType(AVMediaTypeVideo)) {
                // Finally check the position and confirm we've got the back camera
                if(device.position == AVCaptureDevicePosition.Back) {
                    captureDevice = device as? AVCaptureDevice
                    if captureDevice != nil {
                        println("Capture device found")
                        beginSession()           ! Use of unresolved identifier 'beginSession'
                    }
                }
            }

 

[PhoneyDeveloper]

It's a local function. See here

https://github.com/mortenjust/photometer/blob/master/Photometer/MJCamera.swift

or here

https://stackoverflow.com/questions/28487146/how-to-add-live-camera-preview-to-uiview/28487725