How could I self-eject my USB-Drive using the python module 'sub-process'

I have a script for my USB that i need to use on multiple devices, and i want it to auto-eject, and using this method, as long as it has elevated privileges it runs, no issues, no errors, but i check the file explorer and the USB is still in there:

            p = Popen(["diskpart"], stdin=PIPE)
            p.stdin.write(b"select disk " + drive_letter.encode() + b"\n")
            p.stdin.write(b"remove all dismount\n")
            p.stdin.write(b"exit\n")
            print(f"Successfully ejected drive {successful_drive_path}.")

this is all using sub-process module for python, I know I don't need to do this, but I still want to. I suspect it's due to the code being ran in the usb, so maybe i could, with the bat file i use to run and handle everything, run the ejection code using a self-deleting script in the main disk. Idk just ideas.

I believe the issue is that you are call it as a disk, not a volume. This code will fix your issue, but only works with elevated privileges:

def eject_drive(drive_letter=input():
    try:
        p = subprocess.Popen(["diskpart"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)

        # Prepare the diskpart script
        commands = f"""
        select volume {drive_letter}
        remove all dismount
        exit
        """

        # Send the commands
        stdout, stderr = p.communicate(commands)

        if p.returncode == 0:
            print(f"Successfully ejected drive {drive_letter}.")
        else:
            print(f"Failed to eject drive {drive_letter}. Error: {stderr}")
    except Exception as e:
        print(f"Exception occurred: {e}")