How do I include _typename in putItem for AWS Php SDK

I have the following code. I am inserting data into a DynamoDB table, but seems as if not every field will have data in it when I view the data. For example _version, _typename, and etc. How can I add that. I have tried passing _typename but it doesn’t work.

$result = $client->putItem(array(
    'TableName' => 'Package-7u7tfgd6dfaljnar4uqf4rjgi-staging',
    'Item' => array(
        'id' => array('S' => '1204'),
        'description'    => array('S' => 'Local Package'),
        'amount'   => array('N' => '25.93'),
        'quantity' => array('N' => '8'),
        'createdAt'    => array('S' => $time),
        'updatedAt'    => array('S' => $time),
    ),
));