Define class ResultsState and children classes ResultsNotReadyState and ResultsReadyState
Change results_ready field of BaseSim to results_state, with results_ready() method in BaseSim
Only set results_state to either ResultsNotReadyState and ResultsReadyState
Delegate to_json and to_excel methods of BaseSim to those of results_state
Define class ResultsState and children classes ResultsNotReadyState and ResultsReadyState Change results_ready field of BaseSim to results_state, with results_ready() method in BaseSim Only set results_state to either ResultsNotReadyState and ResultsReadyState Delegate to_json and to_excel methods of BaseSim to those of results_state