code: private void addImports(Collection<String> sink,
        Collection<String> paths, Multimap<String, String> publicImports) {
      for (String path : paths) {
        if (sink.add(path)) {
          addImports(sink, publicImports.get(path), publicImports);
        }
      }
    }
docs: Add all paths in {@code paths} to {@code sink}, plus their public imports, recursively.