nb_degrees > 0 is a turn to the right,
nb_degrees < 0 is a turn to the left
blocking is a True/False. If True, your program will wait for this movement to be complete before moving on. If Blocking is set to False, the command will be given to the GPG3 to do the turn but control is returned to your program right away so you can keep on taking sensor readings while the turn is being done.