code: def to_string(self):
          
          items = [
              ('oauth_token', self.key),
              ('oauth_token_secret', self.secret),
          ]
  
          if self.callback_confirmed is not None:
              items.append(('oauth_callback_confirmed', self.callback_confirmed))
          return urlencode(items)
docs: Returns this token as a plain string, suitable for storage.
   
          The resulting string includes the token's secret, so you should never
          send or store this string where a third party can read it.