code: def restrictCheckers(self, allowedMessages):
          
          uselessCheckers = self.findUselessCheckers(allowedMessages)
          # Unregister these checkers
          for checker in uselessCheckers:
              self.unregisterChecker(checker)
docs: Unregister useless checkers to speed up twistedchecker.
  
          @param allowedMessages: output messages allowed in twistedchecker