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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 serialize_packet_id(packet: dict) -> str: """Serialize packet identifiers into one reversable string. 'newkaku_000001_01' 'ikeakoppla_000080_0' 'alectov4_000080_0' """

    # translate protocol in something reversable
    protocol = protocol_translations[packet['protocol']]

    if protocol == UNKNOWN:
        protocol = 'rflink'

    return '_'.join(filter(None, [
        protocol,
        packet.get('id', None),
        packet.get('switch', None),
    ]))