code: def new_rater(self):
          
          if self.annot is None:  # remove if buttons are disabled
              self.parent.statusBar().showMessage('No score file loaded')
              return
  
          newuser = NewUserDialog(self.parent.value('scoring_window'))
          answer = newuser.exec_()
  
          if answer == QDialog.Rejected:
              return
  
          rater_name = newuser.rater_name.text()
  
          if rater_name != '':
              self.annot.add_rater(rater_name, newuser.epoch_length.value())
              self.display_notes()
              self.parent.create_menubar()
docs: Action: add a new rater.