<?php

require_once __DIR__ . "/../vendor/autoload.php";
$service_account = file_get_contents(__DIR__ . '/service_account.json');
$contentOwner = \Tubecode\Factory::create($service_account, [], "YOUR CONTENT OWNER ID");
echo "Count: " . $contentOwner->linkedChannels()->count() . PHP_EOL;
foreach ($contentOwner->linkedChannels()->all() as $channel) {
    echo "ID: {$channel->getId()}" . PHP_EOL;
}
<?php

require_once __DIR__ . "/../vendor/autoload.php";
$service_account = file_get_contents(__DIR__ . '/service_account.json');
$contentOwners = \Tubecode\Factory::create($service_account);
foreach ($contentOwners->all() as $contentOwner) {
    echo "Content owner {$contentOwner->getDisplayName()} ({$contentOwner->getId()})\n";
}