message: Add B field requirement to the Absorption task
diff: @@ -20,6 +20,9 @@ AliAnalysisTaskDeuteronAbsorption* AddTaskDeuteronAbsorption(TString name = "sta
  if (!mgr->GetInputEventHandler()) {
  return 0x0;
  }
  + //
  + AliInputEventHandler* hdl = (AliInputEventHandler*)mgr->GetInputEventHandler();
  + if (hdl) hdl->SetNeedField();
  // by default, a file is open for writing. here, we get the filename
  TString fileName = AliAnalysisManager::GetCommonFileName();
  fileName += ":DeuteronAbsorption"; // create a subfolder in the file
  