public void start(Stage primaryStage) throws Exception {
        scrollPane = new ScrollPane();
        dialogContainer = new VBox();
        scrollPane.setContent(dialogContainer);

        userInput = new TextField();
        sendButton = new Button("Send");

        AnchorPane mainLayout = new AnchorPane();
        mainLayout.getChildren().addAll(scrollPane, userInput, sendButton);

        scene = new Scene(mainLayout);

        primaryStage.setScene(scene);
        primaryStage.show();

        //Step 2. Formatting the window to look as expected
        primaryStage.setTitle("Tach");
        primaryStage.setResizable(true);
        primaryStage.setMinHeight(600.0);
        primaryStage.setMinWidth(400.0);

        mainLayout.setPrefSize(400.0, 600.0);

        scrollPane.setPrefSize(385, 535);
        scrollPane.setHbarPolicy(ScrollPane.ScrollBarPolicy.NEVER);
        scrollPane.setVbarPolicy(ScrollPane.ScrollBarPolicy.ALWAYS);

        scrollPane.setVvalue(1.0);
        scrollPane.setFitToWidth(true);

        // You will need to import `javafx.scene.layout.Region` for this.
        dialogContainer.setPrefHeight(Region.USE_COMPUTED_SIZE);

        userInput.setPrefWidth(325.0);

        sendButton.setPrefWidth(55.0);

        AnchorPane.setTopAnchor(scrollPane, 1.0);

        AnchorPane.setBottomAnchor(sendButton, 1.0);
        AnchorPane.setRightAnchor(sendButton, 1.0);

        AnchorPane.setLeftAnchor(userInput , 1.0);
        AnchorPane.setBottomAnchor(userInput, 1.0);

        sendButton.setOnMouseClicked((event) -> {
            dialogContainer.getChildren().add(getDialogLabel(userInput.getText()));
            dispatcher.handle(userInput.getText());
            userInput.clear();
        });

        userInput.setOnAction((event) -> {
            dialogContainer.getChildren().add(getDialogLabel(userInput.getText()));
            dispatcher.handle(userInput.getText());
            userInput.clear();
        });

        dialogContainer.heightProperty().addListener((observable) -> scrollPane.setVvalue(1.0));
    }

    private static final Map<String, String> DATE_FORMAT_REGEXPS = new HashMap<>() {{
                put("^\\d{8}$", "yyyyMMdd");
                put("^\\d{1,2}-\\d{1,2}-\\d{4}$", "dd-MM-yyyy");
                put("^\\d{4}-\\d{1,2}-\\d{1,2}$", "yyyy-MM-dd");
                put("^\\d{1,2}/\\d{1,2}/\\d{4}$", "MM/dd/yyyy");
                put("^\\d{4}/\\d{1,2}/\\d{1,2}$", "yyyy/MM/dd");
                put("^\\d{1,2}\\s[A-Za-z]{3}\\s\\d{4}$", "dd MMM yyyy");
                put("^[A-Za-z]{3}\\s\\d{1,2}\\s\\d{4}$", "MMM dd yyyy");
                put("^\\d{1,2}\\s[A-Za-z]{4,}\\s\\d{4}$", "dd MMMM yyyy");
                put("^\\d{12}$", "yyyyMMddHHmm");
                put("^\\d{8}\\s\\d{4}$", "yyyyMMdd HHmm");
                put("^\\d{1,2}-\\d{1,2}-\\d{4}\\s\\d{1,2}:\\d{2}$", "dd-MM-yyyy HH:mm");
                put("^\\d{4}-\\d{1,2}-\\d{1,2}\\s\\d{1,2}:\\d{2}$", "yyyy-MM-dd HH:mm");
                put("^\\d{1,2}/\\d{1,2}/\\d{4}\\s\\d{1,2}:\\d{2}$", "MM/dd/yyyy HH:mm");
                put("^\\d{4}/\\d{1,2}/\\d{1,2}\\s\\d{1,2}:\\d{2}$", "yyyy/MM/dd HH:mm");
                put("^\\d{1,2}\\s[A-Za-z]{3}\\s\\d{4}\\s\\d{1,2}:\\d{2}$", "dd MMM yyyy HH:mm");
                put("^\\d{1,2}\\s[A-Za-z]{4,}\\s\\d{4}\\s\\d{1,2}:\\d{2}$", "dd MMMM yyyy HH:mm");
                put("^\\d{14}$", "yyyyMMddHHmmss");
                put("^\\d{8}\\s\\d{6}$", "yyyyMMdd HHmmss");
                put("^\\d{1,2}-\\d{1,2}-\\d{4}\\s\\d{1,2}:\\d{2}:\\d{2}$", "dd-MM-yyyy HH:mm:ss");
                put("^\\d{4}-\\d{1,2}-\\d{1,2}\\s\\d{1,2}:\\d{2}:\\d{2}$", "yyyy-MM-dd HH:mm:ss");
                put("^\\d{1,2}/\\d{1,2}/\\d{4}\\s\\d{1,2}:\\d{2}:\\d{2}$", "MM/dd/yyyy HH:mm:ss");
                put("^\\d{4}/\\d{1,2}/\\d{1,2}\\s\\d{1,2}:\\d{2}:\\d{2}$", "yyyy/MM/dd HH:mm:ss");
                put("^\\d{1,2}\\s[A-Za-z]{3}\\s\\d{4}\\s\\d{1,2}:\\d{2}:\\d{2}$", "dd MMM yyyy HH:mm:ss");
                put("^\\d{1,2}\\s[A-Za-z]{4,}\\s\\d{4}\\s\\d{1,2}:\\d{2}:\\d{2}$", "dd MMMM yyyy HH:mm:ss");
        }};

    /**
     * Determine SimpleDateFormat pattern matching with the given date string. Throws exception if
     * format is unknown. You can simply extend DateUtil with more formats if needed.
     *
     * @param dateString The date string to determine the SimpleDateFormat pattern for.
     * @return The parsed LocalDateTime object.
     * @throws IllegalArgumentException If it cannot parse given string.
     * @see SimpleDateFormat
     */
    public static LocalDateTime parse(String dateString) {
        for (String regexp : DATE_FORMAT_REGEXPS.keySet()) {
            if (dateString.toLowerCase().matches(regexp)) {
                try {
                    return (new SimpleDateFormat(DATE_FORMAT_REGEXPS.get(regexp)).parse(dateString)).toInstant()
                            .atZone(ZoneId.systemDefault())
                            .toLocalDateTime();
                } catch (ParseException e) {
                    throw new IllegalArgumentException(String.format("Matched by cannot parse: %s\n", dateString));
                }
            }
        }
        throw new IllegalArgumentException(String.format("Unknown format: %s\n", dateString));
    }

    /**
     * The main method to launch the program.
     * @param args Command line arguments.
     */

    /**
     * Iteration 1:
     * Creates a label with the specified text and adds it to the dialog container.
     * @param text String containing text to add
     * @return a label with the specified text that has word wrap enabled.
     */

    /**
     * The lambda expression from driver class to indicate exit of the entire program.
     * @param toExit The lambda to trigger program exit.
     */

    /**
     * The main method to launch the program.
     * @param args Command line arguments.
     */

    /**
     * The lambda expression from driver class to indicate exit of the entire program.
     * @param toExit The lambda to trigger program exit.
     */

    /**
     * Add a new speaker.
     * @param s Speaker to add.
     */