How do I code a 3D unit selection box for Godot 4?

I asked ChatGPT the same question, and it gave this answer. I don't know if it's correct:

In Godot 4, the process of creating a 3D unit selection box involves a combination of scripting and utilizing the engine's built-in features. Here's a step-by-step guide to help you code a 3D unit selection box in Godot 4:

Step 1: Setting up the scene

Create a new scene and add a 3D node as the root of the scene.
Add a MeshInstance or Spatial node to represent your selectable units. Ensure that the units have a collider, such as a CollisionShape or CollisionPolygon, attached to them.

Step 2: Implementing the selection box

Create a new script by attaching it to the root node of your scene.
In the script, define a variable to store the initial mouse position when the selection box starts:

var selectionStart: Vector2

Override the _input function to handle mouse input:

func _input(event: InputEvent) -> void:
    if event is InputEventMouseButton:
        var mouseEvent = event as InputEventMouseButton
        
        if mouseEvent.button_index == BUTTON_LEFT and mouseEvent.pressed:
            # Store the initial mouse position
            selectionStart = mouseEvent.position
            
            # Start drawing the selection box
            start_selection_box()
            
        elif mouseEvent.button_index == BUTTON_LEFT and not mouseEvent.pressed:
            # Finish drawing the selection box
            end_selection_box()

Create the start_selection_box function to initialize the selection box:

func start_selection_box() -> void:
    # Create a SelectionBox node
    var selectionBox = SelectionBox.new()
    
    # Add the SelectionBox node to the scene
    add_child(selectionBox)
    
    # Set the initial position of the selection box
    selectionBox.position = selectionStart
    
    # Store the SelectionBox reference in a variable
    $SelectionBox = selectionBox

Implement the end_selection_box function to finalize the selection box and select the units within it:

func end_selection_box() -> void:
    # Get the final mouse position
    var selectionEnd = get_viewport().get_mouse_position()
    
    # Calculate the selection box rectangle
    var selectionRect = Rect2(selectionStart, selectionEnd - selectionStart)
    
    # Iterate over the units in the scene
    for unit in $MeshInstance.get_overlapping_bodies():
        # Check if the unit's position is inside the selection box
        if selectionRect.has_point(unit.global_transform.origin):
            # Perform unit selection logic
            unit.selected = true

Now, create a new script for the SelectionBox node. In this script, define a draw function to draw the selection box:

extends Node2D

func draw() -> void:
    draw_rect(Rect2(Vector2(), get_viewport().get_mouse_position() - position), Color(1, 1, 1, 0.3), true)

Attach the script to the SelectionBox node.

Step 3: Testing the selection box

Instantiate your scene in a scene or as the main scene.
Run the project and test the selection box by clicking and dragging the left mouse button. The units intersecting with the selection box should be selected.

That's it! You have now implemented a basic 3D unit selection box in Godot 4. Feel free to customize and enhance the code according to your specific requirements.