code: def get_accelerator():
      try:
          runtime_conf = _RUNTIME_CONF_VAR.get()
          return runtime_conf.accelerator
      except:  # pylint: disable=bare-except
          return None
  
file_path: towhee/towhee/runtime/runtime_conf.py
imports: import contextvars
  import contextlib
  import functools
label_desc: Use image node_id 3 for calling a global function with example usage: get_accelerator() and returns: runtime_conf, None