code: function(options) {
          OpenLayers.Format.XML.prototype.initialize.apply(this, [options]);
          this.setGeometryTypes();
          if(options && options.featureNS) {
              this.setNamespace("feature", options.featureNS);
          }
          this.singleFeatureType = !options || (typeof options.featureType === "string");
      }
docs: Constructor: OpenLayers.Format.GML.Base
  Instances of this class are not created directly.  Use the
  <OpenLayers.Format.GML.v2> or <OpenLayers.Format.GML.v3> constructor
  instead.
  
  Parameters:
  options - {Object} An optional object whose properties will be set on
  this instance.
  
  Valid options properties:
  featureType - {Array(String) or String} Local (without prefix) feature
  typeName(s) (required for write).
  featureNS - {String} Feature namespace (required for write).
  geometryName - {String} Geometry element name (required for write).