... login name may have many emails. ... wherever the code references $group, its a group_name . ... Works out the TWiki canonical user identifier for the user who either (1) logs in with the login name $identifier or (2) has the wikiname $identifier. ... Return true if $cUID is in a list of user wikinames , logins and group ids. ... This method is called using the login name rather than the $cUID so that it can be called with a user who can be authenticated, but may not be mappable to a cUID (yet). ...