Missing data in prediction

[I don't have a flat head]

Hi!

Appreciate for sharing such greate work!

My concern regarding to the pratical usability of this whole pipeline is: if you select a stock universe i.e., stocks in the CSI300 index, or just simply select n stocks (doesn't really matter), to train the model, then how is the model gonna functioning well (do the right prediction) if some stocks quit the market, or stopped trading for a short period? From my understanding the vertices and edges cannot be missing, and imputing values to nan would lead to inaccurate prediction?

[Hao Yang]

Agree, this is why I am so far still not fully trust GNN could be useful.