code: def close(self):
      if self.closed:
          return
      if self.waiting:
          for remote in self.remotes:
              remote.recv()
      for remote in self.remotes:
          remote.send(("close", None))
      for p in self.ps:
          p.join()
      self.closed = True
  
file_path: keras-rl/rl/common/vec_env/subproc_env_vec.py
imports: import numpy
  from multiprocessing import Process, Pipe
  from rl.common.vec_env import VecEnv, CloudpickleWrapper
  from rl.common.tile_images import tile_images
label_desc: Use image node_id 6 for calling the SubprocVecEnv obj's underlying member method code with example usage: obj.close() without return types