docs: public R setUnsharedAt(Date unsharedAt) throws ParseException {
          JsonObject jsonObject = getSharedLinkJsonObject();
          if (unsharedAt == null){
              jsonObject.add(BoxSharedLink.FIELD_UNSHARED_AT, JsonValue.NULL);
          } else {
              jsonObject.add(BoxSharedLink.FIELD_UNSHARED_AT, BoxDateFormat.format(unsharedAt));
          }
          BoxSharedLink sharedLink = new BoxSharedLink(jsonObject);
          mBodyMap.put(BoxItem.FIELD_SHARED_LINK, sharedLink);
          return (R) this;
      }