Hi, screen works all the time no need to login, you can use nohup too nohup python script.py &.

Also you can create a service for it if you are running Ubuntu 15.04 or newer you can create a simple systemd service file to run it as follows

[Unit]
Description=A test unit

[Service]
ExecStart=<full_path_to_script>
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=hello

Put these lines in a file called hello.service in /etc/systemd/system.

Make sure your script file is executable by running sudo chmod +x <full_path_to_script>

Now reload systemd by running sudo systemctl daemon-reload, start the service sudo systemctl start hello.

Now you can check if the service is running or not using sudo systemctl status hello and stop it using sudo systemctl stop hello

I hope this helps you.