How to use the nfstream.NFPlugin function in nfstream

def test_custom_expiration(self):
        class custom_expire(NFPlugin):
            def on_update(self, obs, entry):
                if entry.bidirectional_packets == 10:
                    entry.expiration_id = -1
                    entry.custom_expire = True

        print("\n----------------------------------------------------------------------")
        streamer_test = NFStreamer(source='tests/pcap/facebook.pcap',
                                   plugins=[custom_expire(volatile=True)],
                                   bpf_filter="src port 52066 or dst port 52066")
        rs = []
        for flow in streamer_test:
            rs.append(flow)
        self.assertEqual(rs[0].expiration_id, -1)
        self.assertEqual(len(rs), 2)
        del streamer_test
        print("{}\t: \033[94mOK\033[0m".format(".Testing custom expiration".ljust(60, ' ')))

def test_user_plugins(self):
        class feat_1(NFPlugin):
            def on_update(self, obs, entry):
                if entry.bidirectional_packets == 4:
                    entry.feat_1 = obs.ip_size

        print("\n----------------------------------------------------------------------")
        streamer_test = NFStreamer(source='tests/pcap/facebook.pcap',
                                   plugins=[feat_1()],
                                   bpf_filter="src port 52066 or dst port 52066")
        rs = []
        for flow in streamer_test:
            rs.append(flow)
        self.assertEqual(rs[0].feat_1, 248)
        self.assertEqual(len(rs), 1)
        del streamer_test
        print("{}\t: \033[94mOK\033[0m".format(".Testing adding user plugins".ljust(60, ' ')))

import argparse
import logging

import dpkt
import pandas as pd
import nfstream
import numpy as np

import settings
from feature_processing import calc_raw_features, calc_flow_features, RMI

logger = logging.getLogger('flow_parser')


class raw_packets_matrix(nfstream.NFPlugin):
    @staticmethod
    def _fill_flow_stats(obs, raw_feature_matrix, counter=0):
        raw_feature_matrix[counter, RMI.TIMESTAMP] = obs.time
        raw_feature_matrix[counter, RMI.IP_LEN] = obs.ip_size
        raw_feature_matrix[counter, RMI.TRANSP_PAYLOAD] = obs.payload_size
        raw_feature_matrix[counter, RMI.TCP_FLAGS] = int(''.join(str(i) for i in obs.tcpflags), 2)
        if obs.protocol == 6 and obs.version == 4:
            packet = dpkt.ip.IP(obs.ip_packet)
            raw_feature_matrix[counter, RMI.TCP_WINDOW] = packet.data.win
        raw_feature_matrix[counter, RMI.IP_PROTO] = obs.protocol
        raw_feature_matrix[counter, RMI.IS_CLIENT] = 1 if obs.direction == 0 else 0
        return raw_feature_matrix

    def on_init(self, obs):
        raw_feature_matrix = np.zeros((settings.PACKET_LIMIT_PER_FLOW, 7))
        return self._fill_flow_stats(obs, raw_feature_matrix)