How to use the mnelab.dialogs.EpochDialog function in mnelab

def epoch_data(self):
        """Epoch raw data."""
        dialog = EpochDialog(self, self.model.current["events"])
        if dialog.exec_():
            events = [int(item.text()) for item
                      in dialog.events.selectedItems()]
            tmin = dialog.tmin.value()
            tmax = dialog.tmax.value()

            if dialog.baseline.isChecked():
                baseline = dialog.a.value(), dialog.b.value()
            else:
                baseline = None

            duplicated = self.auto_duplicate()
            try:
                self.model.epoch_data(events, tmin, tmax, baseline)
            except ValueError as e:
                if duplicated:  # undo