_MultiPolygons ::
  (BaseType a, ListLike f (Geometry Polygon a)) =>
  Iso' (f (Geometry Polygon a)) (Geometry MultiPolygon a)

_MultiPolygons = iso
  (MultiPolygon . foldMap (pure . review _Geometry))
  (foldMap (pure . Polygon)  . review _Geometry)
_MultiPolygons ::
  (BaseType a, ListLike f (Geometry Polygon a)) =>
  Iso' (f (Geometry Polygon a)) (Geometry MultiPolygon a)
_MultiPolygons = iso
  (MultiPolygon . foldMap (pure . review _Geometry))
  (foldMap (pure . Polygon)  . review _Geometry)
_MultiPolygons = iso
  (MultiPolygon . foldMap (pure . review _Geometry))
  (foldMap (pure . Polygon)  . review _Geometry)