问.setText()不工作

EN

function copyDocsAndSetText(fromDirId, toDirId) {
  var toDir = DriveApp.openFolderById(toDirId);
  var cwd = toDir.createFolder("New folder");

  var fromDir = DriveApp.openFolderById(fromDirId);
  var originalFiles = fromDir.getFiles();
  while (originalFiles.hasNext()) {
    var file = originalFiles.next();
    file.makeCopy(cwd);
  }

  var copiedFiles = cwd.getFiles();
  while (copiedFiles.hasNext()) {
    var file = copiedFiles.next();
    var doc = DocumentApp.openById(file.getId());
    doc.getBody().setText("It works!");
  }
}