code: private static Map<String, Integer> daysOfWeekMapping() {
          final Map<String, Integer> stringMapping = new HashMap<>();
          stringMapping.put("MON", 1);
          stringMapping.put("TUE", 2);
          stringMapping.put("WED", 3);
          stringMapping.put("THU", 4);
          stringMapping.put("FRI", 5);
          stringMapping.put("SAT", 6);
          stringMapping.put("SUN", 7);
          return stringMapping;
      }
docs: Creates days of week mapping.
  
  @return Map where strings are weekday names in EEE format and integers correspond to their 1-7 mappings