How to use the natural.Lexicon function in natural

}

    await notice("Obfuscating sentences...");
    await status("Preparing obfuscator...");

    let dummy = d => d;
    let wnet = new WNet({
        dataDir: wnetdb.path
    });
    let tzr = (new natural.TreebankWordTokenizer()).tokenize;
    let isWord = /\w+/;

    let ntrBf = path.join(path.dirname(require.resolve("natural")), "brill_pos_tagger");
    let defaultCat = '?';

    let lex = new natural.Lexicon(ntrBf + "/data/English/lexicon_from_posjs.json", defaultCat);
    let rules = new natural.RuleSet(ntrBf + "/data/English/tr_from_posjs.txt");
    let tagger = new natural.BrillPOSTagger(lex, rules);
    let np = new natural.NounInflector();
    let pvp = new natural.PresentVerbInflector();
    let stmr = natural.PorterStemmer;

    let _accumunator = 0;
    let _total = 0;
    let _st = "";
    let _swp = (w) => ( isWord.test(w[0]) );
    let accumunator = (w) => {
        _accumunator += 1;
        stageHandler.onProgress(_accumunator, _total);
        return w;
    };
    let _stage = (l, s) => {

nlp._init = function () {
    var base_folder = path.join(path.dirname(require.resolve("natural")), "brill_pos_tagger");
    var rulesFilename = base_folder + "/data/English/tr_from_posjs.txt";
    var lexiconFilename = base_folder + "/data/English/lexicon_from_posjs.json";
    var defaultCategory = 'N';

    var lexicon = new natural.Lexicon(lexiconFilename, defaultCategory);
    var rules = new natural.RuleSet(rulesFilename);

    this._tagger = new natural.BrillPOSTagger(lexicon, rules);
    this._tokenizer = new natural.WordTokenizer();
    this._classifier = new RuleClassify(function (classifier) {
        nlp._classifier = classifier;
    });
};