AttendanceRegister backup structure
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* attendanceregister (no user info)
	- if (attr)
	- course (not needed)
	- name
	- intro (fa: attendanceregister_intro, no itemid) ???
	- introformat
	- type
	- offlinesessions
	- sessiontimeout
	- dayscertificable
	- offlinecomments
	- mandatoryofflinecomm
	- offlinespecifycourse
	- mandofflspeccourse
	- timemodified
        - completiontotaldurationmins  (new with version 2.4.3)

* sessions	(user info)
	- id (attr)
	- register (not needed)
	- userid (annotation)
	- login
	- logout
	- duration
	- online
	- refcourseshortname (determined from refcourse)
	- comments
        - addedbyuserid (annotation)