Python重寫stdin和stdout

python的input和print可以重定向如下：

class STDIN:
    def __init__(self):
        self.stdin = sys.stdin

    def readline(self):
        message = '123'
    	return message

class STDOUT:
    def __init__(self, text):
        self.f= open(text,'w')
        self.stdout = sys.stdout
 
    def write(self, message):
        self.stdout.write(message + '\n')
        self.f.write(message)
      
    def flush(self):
        pass