Message
A description should be provided in event-desc for an event with event-type "tagger", "xml-created", "xml-converted", "digitized", or "provenance"
Rule XPath:
This rule ASSERTS the following, raising an alert if FALSE:
if (.[@event-type = ('tagger', 'xml-created', 'xml-converted', 'digitized', 'provenance')])
then .[event-desc] else true()