AVSpeechSynthesisVoice.speechVoices throws an error in Swift

Hi, I’m working on an app which has Text to Speech functionality. I’m developing using Swift , Xcode 7, Mac OS X El Capiton V 10.11.3 . When the program runs I get the following error in this line
AVSpeechSynthesisVoice.speechVoices() and the language code I hard coded to voice out is “en-AU”
Error : 2016-02-29 21:30:37.813 TouristAttractions[2171:210974] |AXSpeechAssetDownloader|error| ASAssetQuery error fetching results (for com.apple.MobileAsset.MacinTalkVoiceAssets) Error Domain=ASError Code=21 “Unable to copy asset information” UserInfo={NSDescription=Unable to copy asset information}

Can you please provide your thoughts on it ?

Any help would be appreciated…