code: def on_all_ok(self):
          
          final_scr = self.merge_scrfiles()
          return self.Results(node=self, returncode=0, message="mrgscr done", final_scr=final_scr)
docs: This method is called when all the q-points have been computed.
          It runs `mrgscr` in sequential on the local machine to produce
          the final SCR file in the outdir of the `Work`.