DialogSession::clearClosedSessions

static function clearClosedSessions(): string
{
	$res = NetworkSessionTable::getList([
		'select' => ['ID', 'CLOSED'],
		'filter' => [
			'!DATE_FINISH' => null,
			'>CLOSE_TERM' => 0,
			'=CLOSED' => 1,
		],
	]);
	while ($sess = $res->fetch())
	{
		NetworkSessionTable::delete($sess['ID']);
	}

	return __METHOD__. '();';
}