Python script to create ROOT friend tree starting from a NANOGEN file. For creating NANOGEN starting from GEN see the makeNanoGEN.py script for example, or refer to https://github.com/kdlong/WMassNanoGen/blob/master/runCmsDriverGenToNanoGEN.sh
Examples:
python -i makefriends.py DYJetsToLL_M-50_TuneCP5_13TeV-amcatnloFXFX-pythia8/13D0AD97-6B32-CB4C-BA87-5E37BA4CF20E.root --xs 6404.4 --output amc.root &
python -i makefriends.py DYToLL_NLO_5FS_TuneCH3_13TeV_matchbox_herwig7_cff_py_GEN_NANOGEN_inNANOAODGEN.root --xs 6009.0 --output h7mbox.root &
python -i makefriends.py DYJetsToLL_M-50_TuneCP5_13TeV-amcatnloFXFX-pythia8/*root --xs 6404.4 --output amc@nlo-py8.root &
python -i makefriends.py PPD-RunIISummer20UL18GEN-00014/497AD23B-7A83-FB4C-A70E-52BB92F1EB54.root --xs 3953 --output herwig_r15.root