$success = $pc->deleteObjectsExpiringBefore( $date, [ $this, 'showProgressAndWait' ] );
if ( !$success ) {
$this->error( "\nCannot purge this kind of parser cache.", 1 );
$success = $pc->deleteObjectsExpiringBefore( $date, [ $this, 'showProgressAndWait' ] );
if ( !$success ) {
$this->error( "\nCannot purge this kind of parser cache.", 1 );