code: def _force(self):
      if self._out is None:
          self._out = np.concatenate(self._frames, axis=-1)
          self._frames = None
      return self._out
  
imports: import numpy
  import os
  from collections import deque
  import gym
  from gym import spaces
  import cv2
  from .wrappers import TimeLimit
label_desc: Use image node_id 2 for calling the LazyFrames obj's underlying member method code with example usage: obj._force() and returns: self