code: function( classInstance, optMethodName, var_args )
      {
          var caller = arguments.callee.caller;
  
          if ( caller.super ) {
              return caller.super.constructor.apply( classInstance,
                                                     Array.prototype.slice.call( arguments, 1 ));
          }
  
          var args = Array.prototype.slice.call( arguments, 2 ), foundCaller = false;
  
          for ( var ctor = classInstance.constructor; ctor;
                ctor = ctor.super && ctor.super.constructor )
          {
              if ( ctor.prototype[ optMethodName ] === caller )
                  foundCaller = true;
              else if ( foundCaller )
                  return ctor.prototype[ optMethodName ].apply( classInstance, args );
          }
      }
docs: convenience method to call the prototype constructor when instantiating
  a function that has been extended (see helpers.extend), e.g. :
  
  helpers.super( this ); can be invoked from the child constructor to
  apply the super class' constructor
  
  adapted from source by The Closure Library Authors
  
  @param {!Function} classInstance the instance of a child class calling this function
  @param {string=} optMethodName optional, when null this invocation should act
  as a super call from the constructor, when given it should match
  a method name present on the prototype of the superclass
  @param {...number} var_args optional arguments to pass to the super constructor