This is an error report.
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Error details
in the file transcription of file fibonacci_action_server.cpp in the notebook, we have at the end the line: FibonacciAction fibonacci("fibonacci"); with this, the recommended commands such as: rostopic echo /fibonacci_as/result dont not work, So, it seems that line should be: FibonacciAction fibonacci("fibonacci_as"); Additionaly, the answer of the exercise has a typo in: roslaunch exercise_413 move_drone_saquare.launch 'saquare' instead of 'square'