Cleaning: raise NotImplemented Exception

there : https://gitlab.aip.de/lketzer/platypos/-/blob/master/platypos_package/Planet_class_LoFo14.py#L312

    def evolve_backwards(self, t_final, initial_step_size, epsilon, K_on,
                         beta_on, evo_track_dict, path_for_saving):
        print("Not implemented yet.")

You could do

    def evolve_backwards(self, t_final, initial_step_size, epsilon, K_on,
                         beta_on, evo_track_dict, path_for_saving):
        raise NotImplementedError("Comming soo... :)")

There is an Exception for it.