Python subprocess (using Popen) hangs indefinitely and doesn't terminate. Why, and how to fix?

My script, utilizing the Popen module in Python, is encountering an issue where it enters a zombie state intermittently and continues running indefinitely.

try:    # Start the subprocess    proc = subprocess.Popen(['your_command'], stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)    output = []    while True:        # Check if there's any output available to read        ready_to_read, _, _ = select.select([proc.stdout], [], [], 0.1)        if proc.stdout in ready_to_read:            line = proc.stdout.readline()            if line:                # Process the line                print(line, end='')  # or do whatever processing you need                output.append(line)            else:                # No more output from subprocess                break        else:            # No output available, do something else or sleep            pass    # Optionally, wait for the process to finish and collect its return code    return_code = proc.wait()

I've provided the path to the batch file here ['your_command'], and within that batch file, I'm invoking the desired Python script. Despite attempting to execute it from the batch script, it's still encountering a halt in execution.