Question for using fn.u_add_v() in nodeflow.apply_block

I want write a minibatch train for GAT.
During full batch training, I write code as:

graph.apply_edges(fn.u_add_v('el', 'er', 'e'))

and in minibatch I create some nodeflow by sampler,so I need to update the edge by using apply_blocks,I write as:

nf.apply_block(block_id,fn.u_add_v('el', 'er', 'e'))

But when I run it, it told me that

I guess fn.u_add_v may not be used in nodeflow? So how can I replace it?
By the way,the how can I use edge_softmax function to update the edge value in nodeflow?

Yes it’s not supported and we are planning to deprecate NodeFlow. The new sampler design can be found at

In the meanwhile, we will fix this bug. Thanks for the report.