def METHOD_NAME(self):
    # winscp will freak out if the server sends version info before the
    # client finishes sending INIT.
    t, data = self._read_packet()
    if t != CMD_INIT:
        raise SFTPError("Incompatible sftp protocol")
    version = struct.unpack(">I", data[:4])[0]
    # advertise that we support "check-file"
    extension_pairs = ["check-file", "md5,sha1"]
    msg = Message()
    msg.add_int(_VERSION)
    msg.add(*extension_pairs)
    self._send_packet(CMD_VERSION, msg)
    return version