public function action_callback( $transaction = null ) {

		$order = $transaction->get_order();

		/**
		 * Filter to avoid sending notification for purchase receipts.
		 *
		 * @since 9.1.2
		 */
		if ( ! apply_filters( 'llms_send_purchase_receipt_notification', true, $order, $transaction ) ) {
			return;
		}

		$this->user_id = $order->get( 'user_id' );
		$this->post_id = $transaction->get( 'id' );

		$this->send();
	}