message: Using time period if the event time stamp is not available, for example in MC
diff: #include <TChain.h>
  #include <TTree.h>
  #include <TMath.h>
  +#include <TTimeStamp.h>
  #include "AliAnalysisTask.h"
  #include "AliAnalysisManager.h"
  #include "AliESDEvent.h"
  @@ -307,9 +308,17 @@ void AliAnalysisTaskAO2Dconverter::UserExec(Option_t *)
  return;
  }
  - if (!fTfInitialized)
  - InitTF(fESD->GetTimeStamp());
  -
  + if (!fTfInitialized) {
  + UInt_t tfId = fESD->GetTimeStamp();
  + if (tfId==0) {
  + // The time stamp of the event is not set, for example in MC
  + // Use the time period from 2020/11/01 in seconds (similar to what we did in the DAQ LDCs)
  + TTimeStamp ts0(2020,11,1,0,0,0);
  + TTimeStamp ts1;
  + tfId = ts1.GetSec() - ts0.GetSec();
  + }
  + InitTF(tfId);
  + }
  // Get multiplicity selection
  AliMultSelection *multSelection = (AliMultSelection*) fESD->FindListObject("MultSelection");
  if (!multSelection)
  