Modifying EXIF Data with Swift 3

EXIFImage-playground.swift

//: Playground - noun: a place where people can play

import UIKit
import ImageIO
import MobileCoreServices

let TEST_IMAGE: String = "replace.jpg"
let beach: UIImage = UIImage(named: TEST_IMAGE)!
let imageData: Data = UIImageJPEGRepresentation(beach, 1)!

let cgImgSource: CGImageSource = CGImageSourceCreateWithData(imageData as CFData, nil)!
let uti: CFString = CGImageSourceGetType(cgImgSource)!
let dataWithEXIF: NSMutableData = NSMutableData(data: imageData)
let destination: CGImageDestination = CGImageDestinationCreateWithData((dataWithEXIF as CFMutableData), uti, 1, nil)!


let imageProperties = CGImageSourceCopyPropertiesAtIndex(cgImgSource, 0, nil)! as NSDictionary
let mutable: NSMutableDictionary = imageProperties.mutableCopy() as! NSMutableDictionary

var EXIFDictionary: NSMutableDictionary = (mutable[kCGImagePropertyExifDictionary as String] as? NSMutableDictionary)!

print("before modification \(EXIFDictionary)")

EXIFDictionary[kCGImagePropertyExifUserComment as String] = "type:video"

mutable[kCGImagePropertyExifDictionary as String] = EXIFDictionary

CGImageDestinationAddImageFromSource(destination, cgImgSource, 0, (mutable as CFDictionary))
CGImageDestinationFinalize(destination)

let testImage: CIImage = CIImage(data: dataWithEXIF as Data, options: nil)!
let newproperties: NSDictionary = testImage.properties as NSDictionary

print("after modification \(newproperties)")

How can we save the images after modifying metadata in document directory?
I tried to save but image saved with old metadata. Modified metadata is lost and image has only original metadata.