text: # coding: utf-8
  
  from abc import ABCMeta, abstractmethod
  
  
  class QuackBehavior(metaclass=ABCMeta):
  
      @abstractmethod
      def quack(self):
          pass
  
  
  class Quack(QuackBehavior):
  
      def quack(self):
          print('くぁっくぁ')
  
  
  class Squeak(QuackBehavior):
  
      def quack(self):
          print('キューキュー')
  