message: Work around for THn Overflow bug in ROOT5
  manual check to not fill over flow bins in THn
  See ROOT bug report:
diff: @@ -201,14 +201,19 @@ void AliAnalysisTaskC2::UserExec(Option_t *)
  multiplicity,
  zvtx};
  for (auto single: this->fsingleHists) {
  + if (// Check overflow; see comments in the loop for the pairs.
  + single->GetAxis(cSinglesDims::kEta)->GetBinLowEdge(1) <= stuffing[cSinglesDims::kEta]
  + && stuffing[cSinglesDims::kEta] < single->GetAxis(cSinglesDims::kEta)->
  + GetBinUpEdge(single->GetAxis(cSinglesDims::kEta)->GetNbins()))
  + {
  single->Fill(stuffing, evWeight * track.weight);
  }
  }
  + }
  {
  Double_t stuffing[3] = {multiplicity, zvtx};
  this->fEventCounter->Fill(stuffing, evWeight);
  }
  - // n: number of valid tracks
  const vector< AliAnalysisC2NanoTrack > tracks = this->GetValidTracks();
  const AliAnalysisC2NanoTrack *trigger, *assoc;
  for (Int_t i = 0; i < tracks.size(); i++) {
  @@ -248,11 +253,15 @@ void AliAnalysisTaskC2::UserExec(Option_t *)
  multiplicity,
  zvtx};
  for (auto pair: this->fpairHists) {
  - // Only envoc fill if we are in the right eta region. If we
  - // filled, move to the next track Ie. Asume that histograms do
  - // not overlap in phace-space so each pair can only go into one
  - // histogram. This is so ugly because ROOT does not report
  - // back if the fill was successful or in an overflow...
  + // Only call Fill if we are in the right eta region. If we
  + // filled, move to the next track. I.e., asume that histograms
  + // do not overlap in phace-space so each pair can only go into
  + // one histogram. This is so ugly because ROOT does not
  + // report back if the fill was successful or in an
  + // overflow. At the same time, there is a problem with ROOT's
  + // THn where filling in an overflow bin might end up in a fill
  + // in a valid bin instead. See
  + // https://sft.its.cern.ch/jira/browse/ROOT-8457
  if (// Check bounderies for eta1
  pair->GetAxis(cPairsDims::kEta1)->GetBinLowEdge(1) <= stuffing[cPairsDims::kEta1]
  && stuffing[cPairsDims::kEta1] < pair->GetAxis(cPairsDims::kEta1)->
  