@Override
  public void registerReferenceProviders(@NotNull PsiReferenceRegistrar registrar) {

    registrar.registerReferenceProvider(psiElement().andOr(Holder.PERCENT_STRING_PATTERN, Holder.FORMAT_STRING_PATTERN),
                                        new PythonFormattedStringReferenceProvider());
  }
@Override
  public void registerReferenceProviders(@NotNull PsiReferenceRegistrar registrar)