docs: private static boolean illegalSchemasFound(Collection<File> schemaFiles) {
      for (final File f : schemaFiles) {
        final Path parent = Paths.get(f.getParent()).toAbsolutePath();
        List<File> matches = FluentIterable.from(schemaFiles).filter(new Predicate<File>() {
          @Override public boolean apply(@Nullable File file) {
            return file != null && file != f && Paths.get(file.getParent()).startsWith(parent);
          }
        }).toList();
  
        if (!matches.isEmpty()) {
          return true;
        }
      }
      return false;
    }