I am using Python, Gmail API and Google Calendar API to retrieve emails and then use those information to make events in Google Calendar. I was able to do this, however I want to rerun these code periodically so it can make new events when new emails are received. Whenever I rerun, I stumble upon duplicates, and I don’t know how I can prevent that. This is my first time using stack overflow, please let me know if you need more details to help me out.