new_contents: # Tai Sakuma <tai.sakuma@cern.ch>
  import ROOT
  from .DelphesEvents import DelphesEvents
  
  ##__________________________________________________________________||
  class DelphesEventBuilder(object):
      def __init__(self, config):
          self.config = config
  
      def __repr__(self):
          return '{}({!r})'.format(
              self.__class__.__name__,
              self.config
          )
  
      def __call__(self):
          file = ROOT.TFile.Open(self.config.inputPath)
          tree = file.Get(self.config.treeName)
          events = DelphesEvents(tree, self.config.maxEvents, self.config.start)
          events.config = self.config
          return events
  
  ##__________________________________________________________________||
  
subject: add a new class DelphesEventBuilder