TransformerManager::checkFormats

static function checkFormats(array &$formats)
{
	$result = [];
	foreach($formats as $key => $format)
	{
		if(!isset(static::getFormats()[$format]))
		{
			return false;
		}
		else
		{
			unset($formats[$key]);
			$result[$format] = $format;
		}
	}

	$formats = $result;

	return true;
}