*/ abstract class MultiSurface extends GeometryCollection { public function project(Projector $projector): MultiSurface { throw new Exception( 'This exception should never be thrown. ' . 'This method is here to ensure that MultiSurface::project() has the correct return type, ' . 'and force concrete classes below MultiSurface to return a MultiSurface, too. ' . 'It cannot be made abstract because GeometryCollection::project() is not abstract.' ); } }