Skimming python CMSSW data format Producers DataFormat python / C++ C++ Events Kappa = KTuple (EDProducer) MVAMETProducer skim.root Events Lumis EDM.root reco::BeamSpot KBeamSpotProducer KBeamSpot reco::PFMET KMETProducer KMET → analysis KElectronMetadata patElectronsProducer pat::Electron KElectronProducer KElectron isoVals … cutbasedID RECO AOD miniAOD CMSSW configuration of producers objects are accepted by label (regex matching) regex producer does the translation, renaming activated in config LCG ROOT dict. dictionary configuration in Tuple scram make