public function keys($class, $view=self::VIEW_DEFAULT)
    {
        if ($provider = $this->nearestForClass($class, 'keys')) {
            return call_user_func($provider, $class, $view);
        }
        return [];
    }
public function keys($class, $view=self::VIEW_DEFAULT)
    {
        if ($provider = $this->nearestForClass($class, 'keys')) {
            return call_user_func($provider, $class, $view);
        }
        return [];
    }
{@inheritdoc}

@param string $class
@param string $view (optional)
@return array Just an indexed array of key names ([id, name, address.street])