Indesign script: export as individual PDF with crop marks

Hi! i just found this script that allows me to export individual PDF from a book. Can you help me add 3mm crop marks to the script? 

I used this script: 

/*

Export Book As Individual PDFs

by m1b, posted here: https://community.adobe.com/t5/indesign-discussions/how-to-export-separate-pdf-files-from-a-book-but-keep-their-original-file-names-help/m-p/12418944#M447167

*/

function main() {

exportBookAsIndividualPDFs({

// 2-number array of 1-based document numbers
// range: undefined, will export all documents of book
// range: [1, 4], exports only the first 4 documents of book
range: undefined,

// name of folder to export pdfs into
// will be created if it doesn't exist
// folder is in same folder as book
folderName: 'PDFs',

// the PDF preset name
PDFPresetName: '[Press Quality]'

});

function exportBookAsIndividualPDFs(params) {
var range = params.range,
folderName = params.folderName,
presetName = params.PDFPresetName;

folderName = folderName || 'PDFs';
PDFPresetName = presetName || '[Press Quality]';

try {

var myPDFExportPreset = app.pdfExportPresets.itemByName(PDFPresetName)
if (!myPDFExportPreset.isValid)
throw 'PDF Preset "' + PDFPresetName + '" is not valid.';

if (app.books.length == 0)
throw 'No books currently open.'

var book = app.books[0],
exportPath = book.filePath + '/' + folderName + '/',
exportFolder = new Folder(exportPath);

// prepare the document range, if specified
if (range == undefined || range.length != 2)
range = [1, book.bookContents.length];

// get the book contents
var bkContents = book.bookContents.itemByRange(range[0] - 1, range[1] - 1);
if (bkContents.constructor.name != 'BookContent')
throw 'Could not get book content for range ' + range + '.'

// this gets file references
var exportDocs = bkContents.fullName;

// set up folder
if (!exportFolder.exists)
exportFolder.create();

// export each document
var i;
for (i = 0, r = range[0] - 1; r < range[1]; i++, r++) {
var doc = exportDocs[i],
filename = doc.name.replace(/\.indd$/, '.pdf'),
exportFile = File(exportPath + filename);

// export
book.exportFile(
ExportFormat.PDF_TYPE,
exportFile,
false,
myPDFExportPreset,
[book.bookContents.item(r)]
);
}

// done
alert(i + ' PDFs exported.');
// reveal folder
exportFile.parent.execute();

} catch (error) {
alert('Export failed\n' + error);
}
}

} // end main

app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Export Book As Individual PDFs');