Cart Page cart table alter

function mymodule_tapir_table_alter(&$table, $table_id) {
  if ($table_id != 'uc_cart_view_table') return;
  
  // Register new column to tapir
  $table['#columns']['price_item'] = array(
    'cell' => t('Price'),
    'weight' => 2.5,
  );
  
  foreach (element_children($table) as $key) {
    if (empty($table[$key]['nid']['#value'])) continue;
      
      // This db-expensive node_load call can be easily avoided by using 
      // single SQL select. But, 
      // that's not so important if visitor usually adds 1-5 products to cart.
      $n = node_load($table[$key]['nid']['#value']);
      $p = uc_price($n -> sell_price, array());     // Add data to our new column
      $table[$key]['price_item'] = array(
         '#value' => $p, 
         '#cell_attributes' => array('class' =>'price-item')
      );   
  }
}

The above code not working for custom category with respect to product.

How i will add new table column for category ?

Please Help me.