return getNodeFailure() != null && getNodeFailure().getCause() instanceof VerificationException;
    }

    public boolean isFailed() {
        return getNodeFailure() != null || getExecutionFailure() != null;
    }

    public boolean isExecuted() {
        return state == ExecutionState.EXECUTED;
    }

    /**

        }
        waitingToStartNodes.add(node);
    }

    private void handleFailure(Node node) {
        Throwable executionFailure = node.getExecutionFailure();
        if (executionFailure != null) {
            // Always abort execution for an execution failure (as opposed to a node failure)
            failures.add(executionFailure);
            abortExecution();