In my store method I am using the $request for Request but when passing to the `Mail::send` method showing an error that undefined variable request.

```
public function store(Request $request)
    {
        $user = new User();
        $user->add_user($request);
        $confirmation_code = ['123456'];
        Mail::send('users.add-user', $confirmation_code, function($message) {
            $message->to($request->get('email'), $request->get('email'))
                ->subject('Verify your email address');
        });
        return redirect('/users')->with('success', ['Thanks for signing up! Please check your email.']); ;
    }

```