Converted the sim_init_values() to the new relax design.
Updated the initial_values() function to the new design.
Updated the sim_pack_data() method to the new relax design.
Fix for the return_error() method.
Updated the return_data() and return_error() methods to the new relax design.
Converted the back_calc() method to the new relax design.
Updated the create_mc_data() method to the new design.
Added a missing import.
Spelling fix in the compilation error message.
Updated the set_selected_sim() method to the new relax design.