Save a single session to an ordered dictionary.

def _add_single_session_to_to_ordered_dict(self, d, dataset_index, recommended_only):
        """
        Save a single session to an ordered dictionary.
        """
        for model_index, model in enumerate(self.models):
            # determine if model should be presented, or if a null-model should
            # be presented (if no model is recommended.)
            show_null = False
            if recommended_only:
                if self.recommendation_enabled:
                    if self.recommended_model is None:
                        if model_index == 0:
                            show_null = True
                        else:
                            continue
                    elif self.recommended_model == model:
                        pass
                    else:
                        continue
                else:
                    if model_index == 0:
                        show_null = True
                    else:
                        continue

            d["dataset_index"].append(dataset_index)
            d["doses_dropped"].append(self.doses_dropped)
            model._to_df(d, model_index, show_null)