@CheckReturnValue
    public Set<ConceptMap> deductions() {
        Set<ConceptMap> answers = new HashSet<>(this.getAnswers());
        this.getAnswers().forEach(ans -> answers.addAll(ans.explanation().deductions()));
        return answers;
    }
@ CheckReturnValue public Set < ConceptMap > deductions ( ) { Set < ConceptMap > answers = new HashSet < > ( this . getAnswers ( ) ) ; this . getAnswers ( ) . forEach ( ans -> answers . addAll ( ans . explanation ( ) . deductions ( ) ) ) ; return answers ; }
@return set of all answers taking part in the derivation of this answer