def __init__(self, tfile, root='PWG2FEMTO'):
if isinstance(tfile, (str, Path)):
tfile = Path(tfile).expanduser()
if not tfile.exists():
raise FileNotFoundError(tfile.absolute())
from ROOT import TFile
tfile = TFile.Open(str(tfile))
self.tfile = tfile
self._rootcontainer = tfile.Get(root)
self.container = self.find_first_subdir(self._rootcontainer)
self.analysis = self.find_first_subdir(self.container)
