code: def set_id(self,this_id):
          
          if self.type == 'NAF':
              return self.node.set('id',this_id)
          elif self.type == 'KAF':
              return self.node.set('wid',this_id)
docs: Set the identifier for the token
          @type this_id: string
          @param this_id: the identifier