code: def format(self):
          
          message = ""
          if self.paragraphs:
              if self.header:
                  message += (self.header + '\n\n')
              message += "\n\n".join(self.paragraphs)
              if self.footer:
                  message += ('\n\n' + self.footer)
          return message
docs: Format the message parts to a string.
  
          :Returns: A string of all the message parts separated into paragraphs,
              with header and footer paragraphs if they were specified in the
              constructor.