[Python] Unable to read output from interactive script in python subprocess.Popen

The following program is used to simulate cmd.exe using subprocess.

import subprocess
import sys
import threading

def handle_output(shell):
while shell:
output = shell.stdout.readline(1)
print(output, end="")
sys.stdout.flush()

subprocess_shell = subprocess.Popen("cmd.exe", shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True)

threading.Thread(target=handle_output, args=(subprocess_shell,), daemon=True).start()

while True:
subprocess_shell.stdin.flush()
cmd = input()
subprocess_shell.stdin.write(cmd + "\n")


When I execute commands like dir, echo, etc. it works fine, but once I run an interactive program like python, there is no output.

Live output from Python subprocess that calls Python script
This is useful when executing python test.py, by setting os.environ['PYTHONUNBUFFERED'] = '1' and env=os.environ, but still, I got nothing on the output when executing python using that method.

It seems that this is related unbuffered-output but setting os.environ['PYTHONUNBUFFERED'] = '1' and env=os.environ isn't suitable for all situations.

When I type python, the program should have the following output

Python 3.10.6 (tags/v3.10.6:9c7b4bd, Aug 1 2022, 21:53:49) [MSC v.1932 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>


however, I got nothing on the output.

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