code: public CurrencyDateCalculatorBuilder<E> crossCcyCalendar(final HolidayCalendar<E> crossCcyCalendar) {
          if (crossCcyCalendar != null) {
              this.crossCcyCalendar = crossCcyCalendar;
          }
          return this;
      }
docs: If brokenDate is not allowed, we do require to check the WorkingWeek and Holiday for the crossCcy when
  validating the SpotDate or a Tenor date.
  @param crossCcyCalendar the set of holidays for the crossCcy
  @return the builder