@Override
    public Value visitIsSet(Expression fn) {
        return Value.booleanValue(!fn.accept(this).isEmpty());
    }
Evaluates the given condition in the current scope.

@param condition the condition to evaluate.
@return the value returned by the condition.
smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/evaluation/RuleEvaluator.java