@Nullable
  static LazyClassLoader createFrom(@Nullable Iterable<? extends File> files, ClassLoader parent) {
    return Iterators.isEmptyCollection(files)? null : new LazyClassLoader(Iterators.map(files, new Function<File, URL>() {
      @Override
      public URL fun(File f) {
        try {
          return f.toURI().toURL();
        }
        catch (MalformedURLException e) {
          throw new AssertionError(e);
        }
      }
    }), parent);
  }
@Nullable
  static LazyClassLoader createFrom(@Nullable Iterable<? extends File> files, ClassLoader parent)