Companionads don't work

[simoheinonen]

<?php

require_once 'vendor/autoload.php';

use PowerLinks\OpenRtb\BidRequest\BidRequest;
use PowerLinks\OpenRtb\Hydrator;

$json = <<< JSON
{
  "id": "foo",
  "imp": [
    {
      "id": "1",
      "video": {
        "companionad": [
          {
            "w": 0,
            "h": 0,
            "mimes": [
              "image/gif",
              "image/jpeg",
              "image/png",
              "video/x-flv"
            ]
          }
        ]
      }
    }
  ]
}
JSON;

/** @var BidRequest $bidRequest */
$bidRequest = Hydrator::hydrate(json_decode($json, true), new BidRequest());

// Throws "Exception: Class PowerLinks\OpenRtb\BidRequest\Companionad does not exist"

From https://www.iab.com/wp-content/uploads/2015/06/OpenRTB-API-Specification-Version-2-3.pdf