src/Application/Config.php
public function extract(string $namespace): Config
    {
        $extracted = $this->get($namespace);
        if (!is_array($extracted)) {
            throw ConfigException::forExtractionFailure($namespace);
        }

        return new self($extracted);
    }
public function extract(string $namespace): Config
    {
        $extracted = $this->get($namespace);
        if (!is_array($extracted)) {
            throw ConfigException::forExtractionFailure($namespace);
        }

        return new self($extracted);
    }
Returns new instance of the config containing only values from the
given namespace.

@param string $namespace
@return Config