code: function(callback) {
                  var ret,
                      isFunc  = Util.type.function(callback),
                      args    = [].slice.call(arguments, 1);
                 
                  if (isFunc)
                      ret     = callback.apply(null, args);
                  
                  return ret;
              }
docs: function do save exec of function
  @param callback
  @param arg1
  ...
  @param argN