docs: function(features, options) {
          var node = this.writeNode("wfs:Transaction", {
              features:features,
              options: options
          });
          var value = this.schemaLocationAttr();
          if(value) {
              this.setAttributeNS(
                  node, this.namespaces["xsi"], "xsi:schemaLocation",  value
              );
          }
          return OpenLayers.Format.XML.prototype.write.apply(this, [node]);
      }