Yosymfony\Spress\Core\Configuration\Configuration::getConfigEnvFilename PHP Method

    private function getConfigEnvFilename($env)
    {
        if (empty($env)) {
            throw new \RuntimeException('Expected a non-empty string as environment name.');
        }
        if (strtolower($env) === 'dev') {
            return $this->configFilename;
        }
        $filename = str_replace(':env', $env, $this->templateEnvFilename);
        return $filename;
    }