public function dimension($name = null, $value = null)
    {
        $query = new Query\Dimensions($this->mongo, $this->entity, $this->ref, $this->dateRange);
        if (!empty($name)) {
            if (!empty($value)) {
                $query->setDimension($name, $value);
            } else {
                $query->setDimension($name);
            }
        }

        return $query;
    }