code: private static void addCodeToRequireCss(JsDoc.Builder header, SoyFileNode soyFile) {
  
      SortedSet<String> requiredCssNamespaces = new TreeSet<>();
      requiredCssNamespaces.addAll(soyFile.getRequiredCssNamespaces());
      for (TemplateNode template : soyFile.getChildren()) {
        requiredCssNamespaces.addAll(template.getRequiredCssNamespaces());
      }
  
      // NOTE: CSS requires in JS can only be done on a file by file basis at this time.  Perhaps in
      // the future, this might be supported per function.
      for (String requiredCssNamespace : requiredCssNamespaces) {
        header.addParameterizedAnnotation("requirecss", requiredCssNamespace);
      }
    }
docs: Appends requirecss jsdoc tags in the file header section.
  
  @param soyFile The file with the templates..