public function setMvcParam(string $paramName, $value = null)
    {
        $value = $value === null ? null : trim($value);
        switch ($paramName) {
            case 'controller' : 
            case 'action' : 
                $this->mvcUrl[$paramName] = $value;
                break;
            default : 
                $this->mvcUrl['params'][$paramName] = $value;
                break;
        }
        return $this;
    }