Implementing filter().successors()?

[yfukai]

The successors() function takes the node_id= argument, while others like node_attrs are used like filter(node_id=node_ids).node_attrs(). Maybe we can unify the ways those are used.

[JoOkuma]

That makes sense.
At first glance, I thought it would be complicated, but it might just be about moving the method and using the intermediate filter object, which is a messy class.