code: def data_item_live(self, data_item):
          
          class LiveContextManager:
              def __init__(self, manager, object):
                  self.__manager = manager
                  self.__object = object
              def __enter__(self):
                  self.__manager.begin_data_item_live(self.__object)
                  return self
              def __exit__(self, type, value, traceback):
                  self.__manager.end_data_item_live(self.__object)
          return LiveContextManager(self, data_item)
docs: Return a context manager to put the data item in a 'live state'.