anchor.diff:      
     }
     
  -}+}
  
positive.code:           .then((_) {
              return TraceAnalysis.fromGpxFile(file).then((traceAnalysis){
                
                TraceRawDataPurger traceRawDataPurger = new TraceRawDataPurger( 1000/12 , 4000  ) ;
                
                TraceRawData data = new TraceRawData();
                data.points = traceAnalysis.points ;
                TraceRawData purgedData = traceRawDataPurger.purge(data);
                TraceAnalysis purgeTraceAnalysis = new TraceAnalysis.fromPoints(purgedData);
                
                Trace trace = new Trace.fromTraceAnalysis(user.login, purgeTraceAnalysis); 
                trace.title = title ;
  
negative.code: 
  library trails;
  
  