Calendar::checkUsers

private function checkUsers($userIds): array
{
	$newUserIds = [];

	$externalUserTypes = BitrixMainUserTable::getExternalUserTypes();

	$result = BitrixMainUserTable::getList([
		'select' => ['ID', 'EXTERNAL_AUTH_ID'],
		'filter' => ['=ID' => $userIds],
	]);
	while ($user = $result->fetch())
	{
		if (!in_array($user['EXTERNAL_AUTH_ID'], $externalUserTypes, true))
		{
			$newUserIds[] = $user['ID'];
		}
	}

	return $newUserIds;
}