docs: public List<GoogleCalendar> getGoogleCalendars() {
          List<GoogleCalendar> googleCalendars = new ArrayList<>();
          for (Calendar calendar : getCalendars()) {
              if (!(calendar instanceof GoogleCalendar)) {
                  continue;
              }
              googleCalendars.add((GoogleCalendar) calendar);
          }
          return googleCalendars;
      }