class_docstr: Base class for callback.
  
  :param verbose: (int)
class_docstr_tok: ["Base","class","for","callback",".",":","param","verbose",":","(","int",")"]
docstr: This method will be called by the model after each call to `env.step()`.
  
  For child callback (of an `EventCallback`), this will be called
  when the event is triggered.
  
  :return: (bool) If the callback returns False, training is aborted early.
docstr_tok: ["This","method","will","be","called","by","the","model","after","each","call","to","`","env.step","(",")","`",".","For","child","callback","(","of","an","`","EventCallback","`",")",",","this","will","be","called","when","the","event","is","triggered",".",":","return",":","(","bool",")","If","the","callback","returns","False",",","training","is","aborted","early","."]
code: def on_step(self) -> bool:
      """
      This method will be called by the model after each call to `env.step()`.
  
      For child callback (of an `EventCallback`), this will be called
      when the event is triggered.
  
      :return: (bool) If the callback returns False, training is aborted early.
      """
      self.n_calls += 1
      self.num_timesteps = self.model.num_timesteps
  
      return self._on_step()
  
imports: import os
  from abc import ABC
  import warnings
  import typing
  from typing import Union, List, Dict, Any, Optional
  import gym
  import numpy
  from stable_baselines.common.vec_env import VecEnv, sync_envs_normalization, DummyVecEnv
  from stable_baselines.common.evaluation import evaluate_policy
  from stable_baselines import logger
label_desc: Use image node_id 10 for calling the BaseCallback obj's underlying member method code with example usage: obj.on_step() and returns: self