class_docstr: Ascend NPU accelerators.
code: def get_visible_accelerator_ids_env_var() -> str:
      return ASCEND_RT_VISIBLE_DEVICES_ENV_VAR
  
file_path: ray/python/ray/_private/accelerators/npu.py
imports: import os
  import glob
  import logging
  from typing import Optional, List, Tuple
  from ray._private.accelerators.accelerator import AcceleratorManager
label_desc: Use image node_id 2 for calling the NPUAcceleratorManager obj's underlying member method code with example usage: obj.get_visible_accelerator_ids_env_var() and returns: ASCEND_RT_VISIBLE_DEVICES_ENV_VAR