src/Core/Configure.php
public static function configured($name = null)
    {
        if ($name !== null) {
            return isset(static::$engines[$name]);
        }

        return array_keys(static::$engines);
    }
public static function configured($name = null)
    {
        if ($name !== null) {
            return isset(static::$engines[$name]);
        }

        return array_keys(static::$engines);
    }
Gets the names of the configured Engine objects.

@param string|null $name Engine name.

@return array Array of the configured Engine objects.