old_contents: /**
   * @const
   * @suppress {const|duplicate}
   */
  var jsts = {};
  
  
  /** @const */
  jsts.geom = {};
  
  
  /**
   * @constructor
   */
  jsts.geom.Geometry = function() {};
  
  
  /**
   * @param {number} buffer Buffer in meters.
   * @return {jsts.geom.Geometry} A JSTS geometry object.
   */
  jsts.geom.Geometry.prototype.buffer = function(buffer) {};
  
  
  /**
   * @param {jsts.geom.Geometry} jstsGeom A JSTS geometry object.
   * @return {jsts.geom.Geometry} A JSTS geometry object.
   */
  jsts.geom.Geometry.prototype.difference = function(jstsGeom) {};
  
  
  /**
   * @param {jsts.geom.Geometry} jstsGeom A JSTS geometry object.
   * @return {jsts.geom.Geometry} A JSTS geometry object.
   */
  jsts.geom.Geometry.prototype.union = function(jstsGeom) {};
  
  
  /** @const */
  jsts.io = {};
  
  
  /**
   * @constructor
   */
  jsts.io.OL3Parser = function() {};
  
  
  /**
   * @param {ol.geom.Geometry} ol3Geom A OL3 geometry object.
   * @return {jsts.geom.Geometry} A JSTS geometry object.
   */
  jsts.io.OL3Parser.prototype.read = function(ol3Geom) {};
  
  
  /**
   * @param {jsts.geom.Geometry} jstsGeom A JSTS geometry object.
   * @return {ol.geom.Geometry} A OL3 geometry object.
   */
  jsts.io.OL3Parser.prototype.write = function(jstsGeom) {};
  
new_contents: /**
   * @const
   * @suppress {const|duplicate}
   * @externs
   */
  var jsts = {};
  
  
  /** @const */
  jsts.geom = {};
  
  
  /**
   * @constructor
   */
  jsts.geom.Geometry = function() {};
  
  
  /**
   * @param {number} buffer Buffer in meters.
   * @return {jsts.geom.Geometry} A JSTS geometry object.
   */
  jsts.geom.Geometry.prototype.buffer = function(buffer) {};
  
  
  /**
   * @param {jsts.geom.Geometry} jstsGeom A JSTS geometry object.
   * @return {jsts.geom.Geometry} A JSTS geometry object.
   */
  jsts.geom.Geometry.prototype.difference = function(jstsGeom) {};
  
  
  /**
   * @param {jsts.geom.Geometry} jstsGeom A JSTS geometry object.
   * @return {jsts.geom.Geometry} A JSTS geometry object.
   */
  jsts.geom.Geometry.prototype.union = function(jstsGeom) {};
  
  
  /** @const */
  jsts.io = {};
  
  
  /**
   * @constructor
   */
  jsts.io.OL3Parser = function() {};
  
  
  /**
   * @param {ol.geom.Geometry} ol3Geom A OL3 geometry object.
   * @return {jsts.geom.Geometry} A JSTS geometry object.
   */
  jsts.io.OL3Parser.prototype.read = function(ol3Geom) {};
  
  
  /**
   * @param {jsts.geom.Geometry} jstsGeom A JSTS geometry object.
   * @return {ol.geom.Geometry} A OL3 geometry object.
   */
  jsts.io.OL3Parser.prototype.write = function(jstsGeom) {};
  
subject: Add missing @extern tag