def corofunc1():
            called[0] += 1
            return event.ReturnValue(insert_events=[evt2], append_events=[evt])
def __add__(self, other):
        assert self.n_classes == other.n_classes, "Number of classes does not match"
        return MulticlassContingencyTable(self.table + other.table,
                                          n_classes=self.n_classes,
                                          class_names=self.class_names)