readMultiSurface(node, objectStack) {
    /** @type {Array<Polygon>} */
    const polygons = pushParseAndPop(
      [],
      this.MULTISURFACE_PARSERS,
      node,
      objectStack,
      this,
    );
    if (polygons) {
      return new MultiPolygon(polygons);
    }
  }
@param {Element} node Node.
@param {Array<*>} objectStack Object stack.
@return {MultiPolygon|undefined} MultiPolygon.