     /// - Returns:an instance of `MXSpaceGraphData` if the data has been restored succesfully. `nil` otherwise
     func loadSpaceGraphData() -> MXSpaceGraphData? {
         guard let storeUrl = self.storeUrl else {
-            MXLog.error("[MXSpaceStore] loadSpaceGraphData failed: storeUrl not defined")
+            MXLog.error("[MXSpaceStore] loadSpaceGraphData: failed: storeUrl not defined")
             return nil
         }
         

    /// - Returns: `true` if the data has been stored properly.`false` otherwise
    func store(spaceGraphData: MXSpaceGraphData) -> Bool {
        guard let storeUrl = self.storeUrl else {
            MXLog.error("[MXSpaceStore] storeSpaceGraphData failed: storeUrl not defined")
            return false
        }
        

    // MARK - Private
    
    private func setUpStoragePaths() {
        var _cacheUrl: URL?
        
        if let applicationGroupIdentifier = MXSDKOptions.sharedInstance().applicationGroupIdentifier {
            _cacheUrl = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: applicationGroupIdentifier)
        } else {
            let cacheDirList = NSSearchPathForDirectoriesInDomains(.cachesDirectory, .userDomainMask, true)
            _cacheUrl = URL(fileURLWithPath: cacheDirList[0])
        }
        
        guard let cacheUrl = _cacheUrl else {
            MXLog.error("[MXSpaceStore] setUpStoragePaths was unable to define cache URL")
            return
        }
