code: public GlobalizationPreferences setCalendar(Calendar calendar) {
          if (isFrozen()) {
              throw new UnsupportedOperationException("Attempt to modify immutable object");
          }
          this.calendar = (Calendar) calendar.clone(); // clone for safety
          return this;
      }
docs: Sets the calendar. If this has not been set, uses default for territory.
  
  @param calendar arbitrary calendar
  @return this, for chaining
  @hide draft / provisional / internal are hidden on Android