@Override
 public Fragment getItem(int position) {
   CheckItem checkItem = mCheckBridge.getmDataSource().get(position);
   Step4CheckItemFragment step4CheckItemFragment =
       Step4CheckItemFragment.create(position, getCount(), checkItem);
   mPageReferenceMap.put(position, step4CheckItemFragment);
   return step4CheckItemFragment;
 }
 @Override
 public int getCount() {
   return mCheckBridge.getCount();
 }