Base::checkAllowedOperation

static function checkAllowedOperation(string $operation): bool
{
	if (self::$allowedOperations === null)
	{
		self::$allowedOperations = [];
	}
	$className = get_called_class();
	if (!isset(self::$allowedOperations[$className]))
	{
		self::$allowedOperations[$className] = array_fill_keys(static::getAllowedOperations(), true);
	}

	return isset(self::$allowedOperations[$className][$operation]);
}