When I copied and pasted the robot_control_class code. there is a yellow warning as below picture

H @fkaraal,

could you tell us what is the error/warning message?

If you just put your mouse over the yellow or red lines in the Code Editor (in the files that are open), the error message is normally shown.

Sometimes the warnings are not really critical.

Could you tell us the exact Unit and the name of the course which are you following when you got this error so that I can try to reproduce it?

Well, I actually think it is ROS Prerequisites Exam based in the category of this post. Let me now check why this course is not shown to me.