protected function getClasses()
    {
        $class = $this->argument('class');

        // set classes
        if ($class) {
            if (class_exists($class)) {
                $classes = [$class];
            } elseif (class_exists($this->config['models_namespace'] . '\\' . $class)) {
                $classes = [$this->config['models_namespace'] . '\\' . $class];
            } else {
                throw new UnexpectedValueException('Classname is not valid.');
            }
        } else {
            $classes = $this->finder->getClassesFromNamespace($this->config['models_namespace']);
        }

        return $classes;
    }