public function setAction($action)
    {
        if (!in_array($action, $this->acceptedValues)) {
            $acceptedValuesString = implode(', ', $this->acceptedValues);
            throw new \Parable\ORM\Exception("Invalid action set, only {$acceptedValuesString} are allowed.");
        }
        $this->action = $action;
        return $this;
    }