Magick++: how do i use magick++ to convert an animated gif to an animated webp?

Question

The main logic code is as follows:

std::vector<Magick::Image> images;
Magick::readImages(&images, input_blob);
for (auto &image : images) {
    image.magick("WEBP");
}

output_blob = new Magick::Blob;
Magick::writeImages(images.begin(), images.end(), output_blob);

When i wrote output_blob data into a file, i got a static webp image.

Q: How can i get an animated webp file?

Thanks in advance!