List recent non-recurring calendar events
Currently it is not possible to check wether calendar events are recurring or not.
Therefore the only way to implement this is by checking for duplicate event-titles.

To implement this, you first have to create a list of all calendar events. Now you have to check for every event-title how often it appears in this list. 
In the end you can add every title that only appears once to a separate list.

Now you should have a list of everything you achieved (only the non-recurring events).