code: def write(self, output_file):
          
          for message_level, message_text in self:
              output_file.write('%s=%s\r\n' % (message_level, message_text))
          output_file.write('\r\n')
docs: Writes this MessageHeader to an output stream.
  
          Messages are written as a sequence of *<message_text-message_level>***=**
          *<message_text-text>* pairs separated by '\r\n'. The sequence is
          terminated by a pair of '\r\n' sequences.