     public class func allOutputDevices() -> [AMAudioDevice] {
         let devices = allDevices()
 
-        return devices.filter({ (let device) -> Bool in
-            return device.channelsForDirection(.Playback) > 0
-        })
+        return devices.filter { device -> Bool in
+            device.channelsForDirection(.Playback) > 0
+        }
     }
 
     /**


        if let preferredStereoChannels = preferredStereoChannelsForDirection(direction) {

            let canSetVolumeCount = preferredStereoChannels.filter { (channel) -> Bool in
                return canSetVolumeForChannel(channel, andDirection: direction)
            }.count

            return canSetVolumeCount == preferredStereoChannels.count

        let status = getPropertyDataArray(address, value: &relatedDevices, andDefaultValue: AudioDeviceID())

        if noErr == status {
            return relatedDevices.map { deviceID -> AMAudioDevice? in
                AMAudioDevice.lookupByID(deviceID)
            }.flatMap { $0 }
        }

        return nil
