How to use the tftpy.TftpPacketTypes.TftpPacketWithOptions function in tftpy

order suitable for sending over the wire.

        This is an abstract method."""
        raise NotImplementedError("Abstract method")

    def decode(self):
        """The decode method of a TftpPacket takes a buffer off of the wire in
        network-byte order, and decodes it, populating internal properties as
        appropriate. This can only be done once the first 2-byte opcode has
        already been decoded, but the data section does include the entire
        datagram.

        This is an abstract method."""
        raise NotImplementedError("Abstract method")

class TftpPacketInitial(TftpPacket, TftpPacketWithOptions):
    """This class is a common parent class for the RRQ and WRQ packets, as
    they share quite a bit of code."""
    def __init__(self):
        TftpPacket.__init__(self)
        TftpPacketWithOptions.__init__(self)
        self.filename = None
        self.mode = None

    def encode(self):
        """Encode the packet's buffer from the instance variables."""
        tftpassert(self.filename, "filename required in initial packet")
        tftpassert(self.mode, "mode required in initial packet")
        # Make sure filename and mode are bytestrings.
        filename = self.filename
        mode = self.mode
        if not isinstance(filename, bytes):

log.debug("Allowing this affront to the RFC of a 4-byte packet")
            fmt = b"!HH"
            log.debug("Decoding ERR packet with fmt: %s", fmt)
            self.opcode, self.errorcode = struct.unpack(fmt,
                                                        self.buffer)
        else:
            log.debug("Good ERR packet > 4 bytes")
            fmt = b"!HH%dsx" % (len(self.buffer) - 5)
            log.debug("Decoding ERR packet with fmt: %s", fmt)
            self.opcode, self.errorcode, self.errmsg = struct.unpack(fmt,
                                                                     self.buffer)
        log.error("ERR packet - errorcode: %d, message: %s"
                     % (self.errorcode, self.errmsg))
        return self

class TftpPacketOACK(TftpPacket, TftpPacketWithOptions):
    """
::

    +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
    |  opc  |  opt1  | 0 | value1 | 0 |  optN  | 0 | valueN | 0 |
    +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
    """
    def __init__(self):
        TftpPacket.__init__(self)
        TftpPacketWithOptions.__init__(self)
        self.opcode = 6

    def __str__(self):
        return 'OACK packet:\n    options = %s' % self.options

    def encode(self):

order suitable for sending over the wire.

        This is an abstract method."""
        raise NotImplementedError("Abstract method")

    def decode(self):
        """The decode method of a TftpPacket takes a buffer off of the wire in
        network-byte order, and decodes it, populating internal properties as
        appropriate. This can only be done once the first 2-byte opcode has
        already been decoded, but the data section does include the entire
        datagram.

        This is an abstract method."""
        raise NotImplementedError("Abstract method")

class TftpPacketInitial(TftpPacket, TftpPacketWithOptions):
    """This class is a common parent class for the RRQ and WRQ packets, as
    they share quite a bit of code."""
    def __init__(self):
        TftpPacket.__init__(self)
        TftpPacketWithOptions.__init__(self)
        self.filename = None
        self.mode = None

    def encode(self):
        """Encode the packet's buffer from the instance variables."""
        tftpassert(self.filename, "filename required in initial packet")
        tftpassert(self.mode, "mode required in initial packet")
        # Make sure filename and mode are bytestrings.
        filename = self.filename
        mode = self.mode
        if not isinstance(filename, bytes):

log.debug("Allowing this affront to the RFC of a 4-byte packet")
            fmt = b"!HH"
            log.debug("Decoding ERR packet with fmt: %s", fmt)
            self.opcode, self.errorcode = struct.unpack(fmt,
                                                        self.buffer)
        else:
            log.debug("Good ERR packet > 4 bytes")
            fmt = b"!HH%dsx" % (len(self.buffer) - 5)
            log.debug("Decoding ERR packet with fmt: %s", fmt)
            self.opcode, self.errorcode, self.errmsg = struct.unpack(fmt,
                                                                     self.buffer)
        log.error("ERR packet - errorcode: %d, message: %s"
                     % (self.errorcode, self.errmsg))
        return self

class TftpPacketOACK(TftpPacket, TftpPacketWithOptions):
    """
::

    +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
    |  opc  |  opt1  | 0 | value1 | 0 |  optN  | 0 | valueN | 0 |
    +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
    """
    def __init__(self):
        TftpPacket.__init__(self)
        TftpPacketWithOptions.__init__(self)
        self.opcode = 6

    def __str__(self):
        return 'OACK packet:\n    options = %s' % self.options

    def encode(self):