docs: def action_spatial(self, action):
      """Given an Action, return the right spatial action."""
      if self.surf.surf_type & SurfType.FEATURE:
        return action.action_feature_layer
      elif self.surf.surf_type & SurfType.RGB:
        return action.action_render
      else:
        assert self.surf.surf_type & (SurfType.RGB | SurfType.FEATURE)