Utm::getUtmSources

static function getUtmSources()
{
	if (!self::canUse())
	{
		return [];
	}

	static $list = null;
	if ($list === null)
	{
		$list = array_column(
			Sender\Internals\Model\MessageUtmTable::query()
				->addSelect('VALUE')
				->where('CODE', 'utm_source')
				->addGroup('VALUE')
				->setCacheTtl(36000)
				->fetchAll()
			,
			'VALUE'
		);
	}

	return $list;
}