message: strict mode for header
diff: @@ -12,6 +12,9 @@ void runOnNano(const char* filePath = "AliAOD.NanoAOD.root")
  mgr->InitAnalysis();
  mgr->PrintStatus();
  + // NOTE enable this for strict mode in which you get an AliFatal also for fields in the header which are accessed but not available
  + // AliNanoAODHeader::SetFatalMode();
  +
  // Create chain of input files
  TChain * chain = new TChain("aodTree");
  chain->Add(filePath);
  