关闭传递给subprocess.Popen的文件对象是否安全？

Question

关闭已传递给Popen的文件对象是否安全？例如：

import subprocess

fp = open('log.txt', 'w')
args = ...
popen = subprocess.Popen(args, stdout=fp)
fp.close() # <--- Is this OK?
popen.wait()