Issues in creation new function

[Abdel-Nasser-Ateeq]

I am trying to create my own function as user-guide recommended. I wrote the following codes in the following paths.

(Path) Package Script_functions=> Class ScriptFunction=> method function

      if (function.equals("myf")){

            return Function_Calc.myf(args);

        } 

I wrote the below code in this path. (Path) Package Script_functions=> Class Functions

public static String myf (String [] args) throws Exception{

                String valToReturn = "Nassser";

                return valToReturn;

}

And I invoked the function as follows:

function x myf But unfortunately, it didn't work.