Can't get MaxMind Reader to work

Question

According to their PHP Packagist repository page https://packagist.org/packages/maxmind-db/reader the following code is all I need to get the reader to work. PHP doesn't seem to like the use MaxMind\Db\Reader;line. Any clue on how to fix this so it uses the reader.

require_once 'vendor/autoload.php';

use MaxMind\Db\Reader;

$reader = new Reader('GeoIP2-City.mmdb');
print_r($reader->get($_SERVER['REMOTE_ADDR']));
$reader->close()

Answer 1

Okay the solution I figured out is that anything that uses the keyword [use] need to be first in the PHP document; e.g. API.