public function get($composite_key, $default_value = null)
    {
        $array_keys = explode($this->separator, $composite_key);
        $container = $this->container;
        
        foreach ($array_keys as $key) {
            if (!$this->hasChild($container, $key)) {
                return $default_value;
            }
            $container = $this->getChild($container, $key);
        }
        return $container;
    }