There are a few tags for courses that have special meaning - they instruct the system to perform a certain operation
nolist- the course will not be included in any of the "list" commands
nocal- the course will not be shown in the course calendar
single- the course will be labeled accordingly in list
- in case of course creation will generate multiple single-time courses for each of the course dates
hide_full- the course will be hidden from lists in case it is full