Tweening of Edges

[pramttl]

I have tried tweening a node, which works fine. But tweening an Edge in an existing particle system is obfuscating. It has not worked for me yet.

The syntax given in the reference is:

    tweenEdge(edge, duration, opts)

How do I specify an edge in a single parameter?

I tried all this, but does not work:

    sys.tweenEdge({"somenode1":"somenode2"},1,{length:50})
    sys.tweenEdge("somenode1":{"somenode2"},1,{length:50})
    sys.tweenEdge({"somenode1":{"somenode2"}},1,{length:50})