docs: function getDayPeriodRules(localeData) {
    const dayPeriodRules = localeData.get(`supplemental/dayPeriodRuleSet/${localeData.attributes.language}`);
    const rules = {};
    if (dayPeriodRules) {
      Object.keys(dayPeriodRules).forEach(key => {
        if (dayPeriodRules[key]._at) {
          rules[key] = dayPeriodRules[key]._at;
        } else {
          rules[key] = [dayPeriodRules[key]._from, dayPeriodRules[key]._before];
        }
      });
    }
  
    return rules;
  }