Add concern

src/Api.php

@@ -8,8 +8,9 @@ use Illuminate\Support\Str;
 use App\Nami\Exceptions\TooManyLoginAttemptsException;
 use Illuminate\Support\Facades\Http;
 use Illuminate\Support\Collection;
+use Zoomyboy\LaravelNami\Concerns\NamiData;
 
-class Api {
+class Api implements NamiData {
 
     public $cookie;
     public $loggedIn = null;

src/Concerns/NamiData.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Zoomyboy\LaravelNami\Concerns;
+
+use Illuminate\Support\Collection;
+
+interface NamiData {
+
+    public function nationalities(): Collection;
+
+}