code: def credentials(self):
          
          if not self._credentials:
              self.refresh(credentials=True)
          return self._credentials
docs: ::
          
              GET /:login/machines/:id?credentials=True
          
          :Returns: known login-password pairs for the machine
          :rtype: :py:class:`dict`
          
          Provisionally re-fetch the machine information with the credentials 
          flag enabled.