transfer pickle using pipe

pipe.py

##########
#parent.py
##########
import subprocess
import pickle
process = subprocess.Popen(
    ['python', 'child.py'],
    stdin=subprocess.PIPE,
    stdout=subprocess.PIPE,
    bufsize=0
)
pickle.dump({'ffff'}, process.stdin)
output = pickle.load(process.stdout)
print(output)


##########
#child.py
##########
import sys
import pickle

input = pickle.load(sys.stdin.buffer)
input.add('cccccc')
pickle.dump(input, sys.stdout.buffer)