def credentials(self):
if not self._credentials:<EOL><INDENT>self.refresh(credentials=True)<EOL><DEDENT>return self._credentials<EOL>
::

    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.