def rmdir(self, path):
return SFTP_OP_UNSUPPORTED<EOL>
Remove a directory if it exists.  The ``path`` should refer to an
existing, empty folder -- otherwise this method should return an
error.

:param str path:
    requested path (relative or absolute) of the folder to remove.
:return: an SFTP error code `int` like ``SFTP_OK``.