The use of close() in shmem_vec_env

[dwyzzy]

Hi! I'm wondering about the close() in shmem_vec_env.py

When initializing the Process, the code uses close() for parent_pipe

https://github.com/openai/baselines/blob/ea25b9e8b234e6ee1bca43083f8f3cf974143998/baselines/common/vec_env/shmem_vec_env.py#L120

After initializing the Process, the code uses close() for child_pipe

https://github.com/openai/baselines/blob/ea25b9e8b234e6ee1bca43083f8f3cf974143998/baselines/common/vec_env/shmem_vec_env.py#L57

So both child_pipe and parent_pipe use close()? How can we use pipe to communicate later?

Could you tell me why use close() here?