FluentDOM\Serializer\Factory\Group::createSerializer PHP Method

    public function createSerializer($contentType, \DOMNode $node)
    {
        $serializer = NULL;
        if ($this->offsetExists($contentType)) {
            $factory = $this->offsetGet($contentType);
            if ($factory instanceof SerializerFactory) {
                $serializer = $factory->createSerializer($contentType, $node);
            } elseif (is_callable($factory)) {
                $serializer = $factory($contentType, $node);
            }
            if (NULL !== $serializer && !method_exists($serializer, '__toString')) {
                throw new Exceptions\InvalidSerializer($contentType, get_class($serializer));
            }
        }
        return $serializer;
    }