-TAG-CHANGES should be a list of strings of the form \"+tag\" or
-\"-tag\" and QUERY should be a string containing the
-search-query.
+QUERY should be a string containing the search-terms.
+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.