code: def _mode_to_opener(self, mode):
      opener = self._mode_to_opener[mode]
      if opener is None:
          raise ValueError(
              "Mode {} not supported by {}",
              mode,
              self.__class__.__name__,
          )
      return opener
  
imports: import random
  import logging
  import multiprocessing
  import threading
  from fiber.backend import get_backend
label_desc: Use image node_id 3 for calling the NNGDevice obj's underlying member method code with example usage: obj._mode_to_opener(mode) and returns: opener