docs: @Override
      public boolean isEmpty() {
          ensureOpen();
  
          String sql = "SELECT COUNT(" + COLUMN_ID + ") FROM " + TABLE_NAME;
          Cursor cursor = getReadableDatabase().rawQuery(sql, null);
          cursor.moveToFirst();
          boolean result = (cursor.getInt(0) == 0);
          cursor.close();
          return result;
      }