google Appscript to covert slides from drive to save as pdf in drive

Question

Need a Google Appscript to convert the Drive Slide presentaion to save as backup pdf

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function backupSlides() {
  // Get all Slides files in the current user's Drive.    
  var slidesFiles = DriveApp.getFilesByName('\*.pptx', {q: 'owner = me' });

  // Loop through each Slides file and create a PDF file.     
  for (var i = 0; i \< slidesFiles.length; i++) {     

    var slidesFile = slidesFiles\[i\];      

    // Create a new PDF file with the same name as the Slides file.     
    var pdfFile = slidesFile.makeCopy('backup.pdf');      

    // Convert the Slides file to a PDF file.     
    var slidesApp = SlidesApp.openById(slidesFile.getId());     

    var pdfApp = PDFApp.create(pdfFile);     

    pdfApp.setSlides(slidesApp);     

    pdfApp.save();  

  } 
}