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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def validate_packet(packet):
 """Check if packet is valid OF packet. Raises: UnpackException: If the packet is invalid. """

    if not isinstance(packet, bytes):
        raise UnpackException('invalid packet')

    packet_length = len(packet)

    if packet_length < 8 or packet_length > 2**16:
        raise UnpackException('invalid packet')

    if packet_length != int.from_bytes(packet[2:4], byteorder='big'):
        raise UnpackException('invalid packet')

    version = packet[0]
    if version == 0 or version >= 128:
        raise UnpackException('invalid packet')