code: public final boolean openAt(@NotNull final DayOpeningHours dayOpeningHours) {
          Contract.requireArgNotNull("dayOpeningHours", dayOpeningHours);
          if (!dayOpeningHours.isNormalized()) {
              throw new ConstraintViolationException(
                      "The argument 'dayOpeningHours' is expected to have only hours of a single day, but was: " + dayOpeningHours);
          }
  
          final int idx = weeklyOpeningHours.indexOf(dayOpeningHours);
          if (idx < 0) {
              return false;
          }
          final DayOpeningHours found = weeklyOpeningHours.get(idx);
          final List<DayOpeningHours> normalized = found.normalize();
          final DayOpeningHours day = normalized.get(0);
  
          return day.openAt(dayOpeningHours);
  
      }
docs: Determines if this instance if "open" at the given day and time ranges. It is only allowed to call this method if the parameter
  'dayOpeningHours' represents only one day. This means a value like 'Fri 18:00-03:00' will lead to an error. To avoid this, call the
  {@link DayOpeningHours#normalize()} function before this one and pass the result per day as an argument to this method.
  
  
  @param dayOpeningHours
  Day and times to verify.
  
  @return {@literal true} if open else {@literal false} if not open.