code: function _getOldNewClassConstructor (classDef) {
      var builder = new _GpfFunctionBuilder(_gpfNewClassConstructorTpl),
          constructorName = classDef.getName().split(".").pop();
      builder.replaceInBody({
          "function": "function " + constructorName
      });
      return builder.generate()(classDef);
  }
docs: Allocate a named class constructor for a class definition
  
  @param {_GpfOldClassDefinition} classDef Class definition
  @returns {Function} Constructor
   Build a new constructor