code: function(collection) {
              var array = [];
              for(var i=0, len=collection.components.length; i<len; ++i) {
                  array.push(this.extractGeometry.apply(this, [collection.components[i]]));
              }
              return array.join(',');
          }
docs: Return the WKT portion between 'GEOMETRYCOLLECTION(' and ')' for an <OpenLayers.Geometry.Collection>
  @param {OpenLayers.Geometry.Collection} collection
  @returns {String} internal WKT representation of the collection