Base class for all objects affected by physics in 2D space.
PhysicsBody2D is an abstract base class for implementing a physics body. All *Body2D types inherit from it.
https://docs.godotengine.org/en/3.4/tutorials/physics/physics_introduction.html
Adds a body to the list of bodies that this body can't collide with.
Returns an array of nodes that were added as collision exceptions for this body.
Removes a body from the list of bodies that this body can't collide with.
Both collision_layer and collision_mask. Returns collision_layer when accessed. Updates collision_layer and collision_mask when modified.