How can I make the player go forward? (Ursina Python)

Question

class Player(Entity):
    def __init__(self):
        self.controller = Entity(
            model = 'cube',
            parent = camera
        )
        super().__init__(parent=self.controller)
        
    def update(self):
        if held_keys['a']:
            camera.rotation_y -= 50 * time.dt
            self.controller.rotation_y = camera.rotation_y
            if camera.rotation_y < -360: camera.rotation_y = 0
            
        if held_keys['d']:
            camera.rotation_y += 50 * time.dt
            self.controller.rotation_y = camera.rotation_y
            if camera.rotation_y > 360: camera.rotation_y = 0

Answer 1

entity = Entity(model='cube')

def update():
    entity.position += entity.forward