question: public void add ( ObjectContract contract ) { List < ObjectContract > contractList = contractMap . get ( contract . getArity ( ) ) ; if ( contractList == null ) { contractList = new ArrayList < > ( ) ; } contractList . add ( contract ) ; contractMap . put ( contract . getArity ( ) , contractList ) ; if ( contract . getArity ( ) > maxArity ) { maxArity = contract . getArity ( ) ; } }
target:  Adds a contract to this set.