I am attempting to create a simple SVG animation using SVG.js. My desired result would be equivalent to:

<filter">
  <feDiffuseLighting result="diffOut" in="SourceGraphic" diffuseConstant="1.2"
    lighting-color="white">
    <feDistantLight azimuth="240" elevation="100">
        <animate attributeName="elevation"
            values="100; 20" dur="7s"
         />
     </feDistantLight>
  </feDiffuseLighting>
  <feComposite in="SourceGraphic" in2="diffOut" operator="arithmetic"
     result="diffPointOut" k1="1" k2="0" k3="0" k4="0" />
</filter>

As of now I was able to replicate everything but the animation via using svg.js and svg.filter.js:

foreground.filterWith(function (filter) {
    diff = filter.diffuseLighting().attr({
        'lighting-color': 'white',
        'diffuseConstant': 1.2
    });
    dLight = SVG('<feDistantLight azimuth="240" elevation="100"/>');
    diff.add(dLight);

    filter.composite(filter.source, diff)
        .attr({
            operator: 'arithmetic',
            k1: 1, k2: 0, k3: 0, k4: 0
        });
});

This snippet of code generates in resulting DOM the exact same filter without the animation To add an animation I've attempted to use:

 dLight.animate(7000, 0, 'now').attr({ "elevation": 20 });

But it causes an error declaring, that 'dLight' has no function named 'animate'. If I try to create my own svg.js animation runner and pass dLight to it, it would cause a similar error, declaring, that it doesn't have a '_prepareRunner' function.

On the other hand I can animate any attribute of 'diff' - the diffuseLight filter just fine. Which means my trouble is probably caused by a way I used to create distantLightFilter via SVG(...) method, but I found no other method to create it, since as according to last post here: https://github.com/svgdotjs/svg.filter.js/issues/18 the svg.filter.js does not provide a constructor for it anymore.
I am looking for help in either adding an animation to result of SVG(...) call or creating a distantLight filter in more proper animatable way.