class_docstr: Raised when an asynchronous step is not running but
  step_wait() is called.
code: def __init__(self):
      msg = "not running an async step"
      Exception.__init__(self, msg)
  
imports: from abc import ABC, abstractmethod
  import inspect
  import pickle
  from typing import Sequence, Optional, List, Union
  import cloudpickle
  import numpy
  from stable_baselines import logger
  from stable_baselines.common.tile_images import tile_images
label_desc: Use image node_id 1 to create a new NotSteppingError object from inherited base classes: Exception with example: obj = NotSteppingError()