Manager::checkIsSubEntityKey

static function checkIsSubEntityKey($key)
{
	$key = trim($key);
	if((string) $key == '')
	{
		return false;
	}

	if(mb_strpos($key, static::SE_PREFIX) === 0)
	{
		$key = mb_substr($key, mb_strlen(static::SE_PREFIX), mb_strlen($key) - mb_strlen(static::SE_PREFIX));
		$legal = array_flip(static::getLegalSubEntities());

		return isset($legal[$key]) ? $key : false;
	}

	return false;
}