protected function getCustomCommandName($commandClass)
    {
        if (!class_exists($commandClass)) {
            throw new ConfigurationException("Extension: Command class $commandClass not found");
        }

        $interfaces = class_implements($commandClass);

        if (!in_array('Codeception\CustomCommandInterface', $interfaces)) {
            throw new ConfigurationException("Extension: Command {$commandClass} must implement " .
                                             "the interface `Codeception\\CustomCommandInterface`");
        }

        return $commandClass::getCommandName();
    }