code: int getElementID(int column) {
          if (cells[column] == null) return NULL;
          else if (Cell.class.isInstance(cells[column])) return CELL;
          else if (Table.class.isInstance(cells[column])) return TABLE;
          
          return -1;
      }
docs: Returns the type-id of the element in a Row.
  
  @param       column  the column of which you'd like to know the type
  @return the type-id of the element in the row