In Course ROS TF, Unit 3, Publish ad SUbscribe to TF data, , using the file
multiple_broadcatser.py, we get the position of the models in Gazebo using the line
pose_now = gazebo_model_object.get_model_pose(robot_name).
gazebo_model_object is an object of the class GazeboModel (which is from turtle_tf_3d.get_model_gazebo_pose).
Question: When we receive position and orientation information using function get_model_pose(), which was published by Gazebo, what is the reference frame for all the models, is it world by default?