              return
          if self._backend == "cpu":
              logger.verbose("Hiding GPUs from Tensorflow")  # type:ignore
              tf.config.set_visible_devices([], "GPU")
              return
  
          gpus = tf.config.list_physical_devices('GPU')
          if exclude_gpus:
              gpus = [gpu for idx, gpu in enumerate(gpus) if idx not in exclude_gpus]
              logger.debug("Filtering devices to: %s", gpus)
 
</s> remove             return
 </s> add             return retval </s> remove     def _set_session(self, allow_growth: bool, exclude_gpus: list) -> None:
 </s> add     def _set_session(self,
                     allow_growth: bool,
                     exclude_gpus: list,
                     cpu_mode: bool) -> ContextManager: </s> remove             kwargs = {"minsize": 20,  # minimum size of face
                      "threshold": [0.6, 0.7, 0.7],  # three steps threshold
                      "factor": 0.709}               # scale factor
 </s> add             kwargs = {}
            return retval
              return
          if self._backend == "cpu":
              logger.verbose("Hiding GPUs from Tensorflow")  # type:ignore
              tf.config.set_visible_devices([], "GPU")
            return retval
  
          gpus = tf.config.list_physical_devices('GPU')
          if exclude_gpus:
              gpus = [gpu for idx, gpu in enumerate(gpus) if idx not in exclude_gpus]
              logger.debug("Filtering devices to: %s", gpus)
keep keep keep keep replace keep keep keep keep keep
 Add CPU option to BiSeNet and MTCNN
  - Add CPU option to KSession
  - MTCNN optimizations
  - Update docs for bisenet + mtcnn 
lib/model/session.py