def METHOD_NAME():
    instance = HostBase()
    test_data = {field: None for field in WS_FIELDS}
    test_data.update({
        'tcp.srcport': 99,
        'tcp.dstport': 100,
    })
    mac_df = recast_df(pd.DataFrame([test_data]))
    assert instance._lowest_ip_proto_port(mac_df, 'tcp') == {99}