How to tell Godot that a wall is a wall (searching answer day 1)

Godot Version

4.2.2

Question

what counts as a wall when using tilemap? or how to tell godot what is a wall?
i am using func is_on_wall()

Create a class called Wall

And on collision check if body is Wall

Or you can add the “wall” object to a wall group.

And on collision check if body.is_in_group("wall")

From the CharacterBody2D is_on_wall() documentation:

The up_direction and floor_max_angle are used to determine whether a surface is “wall” or not.