def chattr(self, attr):
return SFTP_OP_UNSUPPORTED<EOL>
Change the attributes of this file.  The C{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 attr: the attributes to change on this file.
@type attr: L{SFTPAttributes}
@return: an error code like L{SFTP_OK}.
@rtype: int