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func addWaterMark(toVideofrom url: URL, onComplete: @escaping (URL?, UIImage?) -> Void) {
        let queue = DispatchQueue.global(qos: .background)
        queue.async { [self] in
           1// let asset = AVURLAsset(url: url)
            2//let composition = AVMutableComposition()
            
           3// guard
             let compositionVideoTrack = composition.addMutableTrack(
                withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid),
             let assetVideoTrack = asset.tracks(withMediaType: .video).first
              else {
                print("Something is wrong with the asset.")
                onComplete(nil, nil)
                return
            }
            
           4// do {
              let timeRange = CMTimeRange(start: .zero, duration: asset.duration)
              try compositionVideoTrack.insertTimeRange(timeRange, of: assetVideoTrack, at: .zero)
          5//  if let assetAudioTrack = asset.tracks(withMediaType: .audio).first,
                let compositionAudioTrack = composition.addMutableTrack(
                  withMediaType: .audio,
                  preferredTrackID: kCMPersistentTrackID_Invalid) {
                try compositionAudioTrack.insertTimeRange(
                  timeRange,
                  of: assetAudioTrack,
                  at: .zero)
              }
            } catch {
              print(error)
                onComplete(nil, nil)
              return
            }