documentation/module-backend_2_model_2_widget_2_grid_2_totals_interface_8php_source.html

 <?php
 namespace Magento\Backend\Model\Widget\Grid;

 interface TotalsInterface
 {
     public function countTotals($collection);
 }
Magento\Backend\Model\Widget\Grid\TotalsInterface
Definition: TotalsInterface.php:12

Magento\Backend\Model\Widget\Grid\TotalsInterface\countTotals
countTotals($collection)

Magento\Backend\Model\Widget\Grid
Definition: AbstractTotals.php:7

$collection
$collection
Definition: catalog_category_with_apostrophe_rollback.php:17