code: def serialize(self):
          
          res = super(Timeperiod, self).serialize()
  
          res['dateranges'] = []
          for elem in self.dateranges:
              res['dateranges'].append({'__sys_python_module__': "%s.%s" % (elem.__module__,
                                                                            elem.__class__.__name__),
                                        'content': elem.serialize()})
  
          return res
docs: This function serialize into a simple dict object.
          It is used when transferring data to other daemons over the network (http)
  
          Here we directly return all attributes
  
          :return: json representation of a Timeperiod
          :rtype: dict