static L<File> deleteFilesVerbose(File... files) {
  ret deleteFilesVerbose(asList(files));
}

static L<File> deleteFilesVerbose(L<File> files) {
  new L<File> out;
  for (File f : unnull(files))
    if (deleteFileVerbose(f)) out.add(f);
  ret out;
}