code: def labels_and_ticks(self):
          
          labels, idxs = [], []
          for plotter in self.plotters.values():
              sub_labels, sub_idxs, _, _ = plotter.labels_ticks_and_vals()
              labels.append(sub_labels)
              idxs.append(sub_idxs)
          return np.concatenate(labels), np.concatenate(idxs)
docs: Collect labels and ticks from plotters.