code: def is_valid(self) -> bool:
      # If the entry doesn't have a reference type or some invalid state,
      # (e.g., no object ref presented), it is considered invalid.
      if (
          not self.pinned_in_memory
          and self.local_ref_count == 0
          and self.submitted_task_ref_count == 0
          and len(self.contained_in_owned) == 0
      ):
          return False
      elif self.object_ref.is_nil():
          return False
      else:
          return True
  
imports: import base64
  import logging
  from collections import defaultdict
  from enum import Enum
  from typing import List
  import ray
  from ray._private.internal_api import node_stats
  from ray._raylet import ActorID, JobID, TaskID
label_desc: Use image node_id 2 for calling the MemoryTableEntry obj's underlying member method code with example usage: obj.is_valid() and returns: False, False, True