public static function event_fees( $event_id ) {
		$orders            = self::get_orders( $event_id );
		$valid_order_items = self::get_valid_order_items_for_event( $event_id, $orders );

		$fees = 0;

		foreach ( $valid_order_items as $order_id => $order ) {
			if ( 'cancelled' === $orders[ $order_id ]['status']
			     || 'refunded' === $orders[ $order_id ]['status']
			     || 'failed' === $orders[ $order_id ]['status']
			) {
				continue;
			}

			$order_total = 0;

			foreach ( $order as $line_item ) {
				$order_total += $line_item['subtotal'];
			}

			$fees += self::calc_site_fee( $order_total, self::$pass_fees_to_user );
		}

		return $fees;
	}