protected function renderManagerFile(EntityStackConfiguration $configuration)
    {
        $intercessionClass = $this->makeManagerIntercessionClass($configuration);

        $dir = $configuration->getEntityDir();

        if (!is_writable($dir)) {
            throw new NotWritableException($dir);
        }

        $this->getGenerator()->createClassDefinitionFile($intercessionClass, $configuration->getManagerPath());
    }