public Pair<String, LangModel> getLangTokens(String lang) {
        String actualLangCode = getActualLangCode(lang);
        return Pair.of(actualLangCode, commonTokenMap.get(actualLangCode));
    }
@param lang
@return pair of actual language code used and a set of common
tokens for that language
tika-eval/tika-eval-core/src/main/java/org/apache/tika/eval/core/tokens/CommonTokenCountManager.java