Usage:

python server.py

The server will be available at port 8052.

Alternatively, to run it as a daemon, try a sample systemd service:

[Unit]
Description=PTV server
After=network.target

[Service]
Type=simple
Restart=always
ExecStart=/usr/bin/python3 /opt/ptvtt/server.py

[Install]
WantedBy=multi-user.target

Note that you will need a PTV Timetable Service Dev ID and API key, see https://www.ptv.vic.gov.au/footer/data-and-reporting/datasets/ptv-timetable-api/ptv-timetable-api-faqs/ on how to get one.