Doctrine\ODM\MongoDB\Mapping\Driver\YamlDriver::setShardKey PHP Method

    private function setShardKey(ClassMetadataInfo $class, array $shardKey)
    {
        $keys = $shardKey['keys'];
        $options = array();
        if (isset($shardKey['options'])) {
            $allowed = array('unique', 'numInitialChunks');
            foreach ($shardKey['options'] as $name => $value) {
                if (!in_array($name, $allowed, true)) {
                    continue;
                }
                $options[$name] = $value;
            }
        }
        $class->setShardKey($keys, $options);
    }