use DevMob\Postcodes\Providers\PostcodeApiNu\PostcodeApiNu;

$provider = new PostcodeApiNu([
    'key' => 'YOUR_API_KEY',
]);
$address = $provider->lookup('3011ED', '50');

use DevMob\Postcodes\Providers\ApiPostcode\ApiPostcode;

$provider = new ApiPostcode([
    'token' => 'YOUR_TOKEN',
]);
$address = $provider->lookup('3011ED', '50');