old_contents: # Tai Sakuma <tai.sakuma@cern.ch>
  
  ##____________________________________________________________________________||
  class EventReaderCollectorAssociator(object):
  
      """This class relates event readers and a result collector.
  
      An instance of this class is initialized with a reader class and a
      collector.
  
      When the method ``make()`` is called with a data set name, this
      class creates a reader, provide the collector with the pair of
      the data set name and the reader, and returns the reader.
  
      After the readers read events, the mothod ``collect`` is called.
      This method, in turn, calls the method ``collect`` of the
      collector.
  
      """
  
      def __init__(self, ReaderClass, resultCollector = None):
          self._ReaderClass = ReaderClass
          self._resultCollector = resultCollector if resultCollector is not None else NullCollector()
  
      def make(self, datasetName):
          reader = self._ReaderClass()
          self._resultCollector.addReader(datasetName, reader)
          return reader
  
      def collect(self):
          return self._resultCollector.collect()
  
  ##____________________________________________________________________________||
  class NullCollector(object):
      def collect(self): return None
      def addReader(self, datasetName, reader): pass
  
  ##____________________________________________________________________________||
  
new_contents: # Tai Sakuma <tai.sakuma@cern.ch>
  
  ##____________________________________________________________________________||
  class EventReaderCollectorAssociator(object):
  
      """This class relates event readers and a result collector.
  
      An instance of this class is initialized with a reader class and a
      collector.
  
      When the method ``make()`` is called with a data set name, this
      class creates a reader, provide the collector with the pair of
      the data set name and the reader, and returns the reader.
  
      After the readers read events, the mothod ``collect`` is called.
      This method, in turn, calls the method ``collect`` of the
      collector.
  
      """
  
      def __init__(self, ReaderClass, resultCollector = None):
          self._ReaderClass = ReaderClass
          self.collector = resultCollector if resultCollector is not None else NullCollector()
  
      def make(self, datasetName):
          reader = self._ReaderClass()
          self.collector.addReader(datasetName, reader)
          return reader
  
      def collect(self):
          return self.collector.collect()
  
  ##____________________________________________________________________________||
  class NullCollector(object):
      def collect(self): return None
      def addReader(self, datasetName, reader): pass
  
  ##____________________________________________________________________________||
  
subject: rename a variable in EventReaderCollectorAssociator