-TAG-CHANGES can take multiple forms. If TAG-CHANGES is a list of
-strings of the form \"+tag\" or \"-tag\" then those are the tag
-changes applied. If TAG-CHANGES is a string then it is
-interpreted as a single tag change. If TAG-CHANGES is the string
-\"-\" or \"+\", or null, then the user is prompted to enter the
-tag changes.
+TAG-CHANGES is a list of strings of the form \"+tag\" or
+\"-tag\" to add or remove tags, respectively.