def chattr(self, attr):
return SFTP_OP_UNSUPPORTED<EOL>
Change the attributes of this file.  The ``attr`` object will contain
only those fields provided by the client in its request, so you should
check for the presence of fields before using them.

:param .SFTPAttributes attr: the attributes to change on this file.
:return: an `int` error code like ``SFTP_OK``.