text: from abc import ABCMeta, abstractmethod
  
  
  class IStream(metaclass=ABCMeta):
  
      @abstractmethod
      def read(self, maxbytes=-1):
          pass
  
      @abstractmethod
      def write(self, data):
          pass
  
  
  class SocketStream(IStream):
  
      def read(self, maxbytes=-1):
          pass
  
      def write(self, data):
          pass
  
  
  
  if __name__ == '__main__':
      # a = IStream()
      b = SocketStream()
  