def add(self, entity):
verify_attrs(entity, [('width'), 'height'])
entity.register_handler('input', self.handle_input)
def add(self, entity):
verify_attrs(entity, ['angle', ('va', 0)])
entity.register_handler('update', self.handle_update)
entity.register_handler('input', self.handle_input)
def add(self, entity):
verify_attrs(entity, [('vx', 0), ('vy', 0)])
entity.register_handler('input', self.handle_input)
