def METHOD_NAME(self, fallback_on_lane_0=False):
    """
    Return the single-image GUI for the currently selected image lane.
    If it doesn't exist yet, create it.
    """
    if self._imageLaneIndex is None:
        if fallback_on_lane_0:
            self._imageLaneIndex = 0
        else:
            return None
    # Create first if necessary
    if self._guis[self._imageLaneIndex] is None:
        self._guis[self._imageLaneIndex] = self.singleImageGuiFactory(self._imageLaneIndex)
    return self._guis[self._imageLaneIndex]