protected function notFound()
    {
        $closest   = [];
        $attempted = $this->argv[1];
        $available = \array_keys($this->commands() + $this->aliases);

        foreach ($available as $cmd) {
            $lev = \levenshtein($attempted, $cmd);
            if ($lev > 0 || $lev < 5) {
                $closest[$cmd] = $lev;
            }
        }

        $this->io()->error("Command $attempted not found", true);
        if ($closest) {
            \asort($closest);
            $closest = \key($closest);
            $this->io()->bgRed("Did you mean $closest?", true);
        }

        return ($this->onExit)(127);
    }