class_docstr: Google TPU accelerators.
code: def get_visible_accelerator_ids_env_var() -> str:
      return TPU_VISIBLE_CHIPS_ENV_VAR
  
imports: import os
  import re
  import glob
  import requests
  import logging
  from typing import Dict, Optional, List, Tuple
  from ray._private.accelerators.accelerator import AcceleratorManager
label_desc: Use image node_id 2 for calling the TPUAcceleratorManager obj's underlying member method code with example usage: obj.get_visible_accelerator_ids_env_var() and returns: TPU_VISIBLE_CHIPS_ENV_VAR