anchor.diff:    }
   
     initializeTimeZone(source).then((_) {
  -    final newLocationDatabase = filterTimeZoneData(LocationDatabase.instance,
  +    final result = filterTimeZoneData(LocationDatabase.instance,
           dateFrom: from,
           dateTo: to);
   
  -    return new File(output).writeAsBytes(newLocationDatabase.toBytes()).then((_) {
  -      print('Finished');
  +    final newDB = result.i1;
  +    final report = result.i2;
  +
  +    return new File(output).writeAsBytes(newDB.toBytes()).then((_) {
  +      print('Locations: ${report.originalLocationsCount} => ${report.newLocationsCount}');
  +      print('Transitions: ${report.originalTransitionsCount} => ${report.newTransitionsCount}');
         exit(0);
       });
   
  
positive.code: /// Minimum value for time instants.
  const int _alpha = -_omega;
  
  LocationDatabase filterTimeZoneData(LocationDatabase db, {int dateFrom: _alpha,
      int dateTo: _omega}) {
    final result = new LocationDatabase();
  
    for (final l in db.locations.values) {
      final transitionsCount = l.transitionAt.length;
      final newTransitionAt = [];
      final newTransitionZone = [];
  
  
negative.code: 
      result.add(
          new Location(l.name, newTransitionAt, newTransitionZone, l.zones));
      report.newLocationsCount++;
    }
  
    return new Tuple2(result, report);
  }
  
  void main(List<String> arguments) {
  