question: public List < ChallengeHandler > lookup ( String location ) { List < ChallengeHandler > result = Collections . emptyList ( ) ; if ( location != null ) { Node < ChallengeHandler , UriElement > resultNode = findBestMatchingNode ( location ) ; if ( resultNode != null ) { return resultNode . getValues ( ) ; } } return result ; }
target:  Locate all challenge handlers to serve the given location.