public function set($name, $value = null, $namespace = null)
    {
        // Get the old value of the variable
        $old = $this->get($name, $namespace);

        // Get SESSION Namespace
        $namespace = $this->getNamespace($namespace);

        if (is_null($value)) {
            unset($_SESSION[$namespace][$name]);
        } else {
            $_SESSION[$namespace][$name] = $value;
        }

        return $old;
    }