This code was created to make control plots and cross-checks for the CMS PbPb efficiency tables, will run only over RECODEBUG, but can be an example of track selection and how to access/apply the efficiency tables.
The control plots and cross checks can be found on this presentation: https://indico.cern.ch/event/892187/contributions/3763284/attachments/1992965/3323701/genttrk_2402.pdf