Add methods to standard interface

Hello,

I am on EP7.0 ERP05 NW04s and trying to modify standard ESS applications. When we create a webdynpro application there are certain standard interfaces defined in the Navigator -> gen_wdp -> packages -> com -> sap -> <Application name> -> wdp -> <IPublic <Application name>Component >interface .....I want to know whether we can add methods to this standard interface for our requirements ...because on the top of this file there is a statement like :

This file has been generated by the Web Dynpro Code Generator.

// DO NOT MODIFY! CHANGES WILL BE LOST IF THE FILE IS REGENERATED.

Any help would be highly appreciated.