code: def get_entity(
              self, entity_type, entity_id, history_index=-1, connected=True):
          
  
          if history_index < 0 and history_index != -1:
              history_index += len(self.entity_history(entity_type, entity_id))
              if history_index < 0:
                  return None
  
          try:
              self.entity_data(entity_type, entity_id, history_index)
          except IndexError:
              return None
  
          entity_class = get_entity_class(entity_type)
          return entity_class(
              entity_id, self.model, history_index=history_index,
              connected=connected)
docs: Return an object instance for the given entity_type and id.
  
          By default the object state matches the most recent state from
          Juju. To get an instance of the object in an older state, pass
          history_index, an index into the history deque for the entity.