extractQueryLanguage = (queryLanguage) => {
    if (Array.isArray(queryLanguage)) {
      return queryLanguage.find((lang) => lang !== '' && lang)
    }
    return typeof queryLanguage === 'string' && queryLanguage
  }
@param queryLanguage - language query parameter, either an array or a string.
@return the first non-empty language query parameter found, null otherwise.