mols is none

[lxlsu]

hello,
when I run the model with the data download by the download_dataset.sh, I found that list "mols" returned by the function of "matrices2mol" is None(code in solver.py, ).
···
mols = [self.data.matrices2mol(n_.data.cpu().numpy(), e_.data.cpu().numpy(), strict=True) for e_, n_ in zip(edges_hard, nodes_hard)]
···
And I have no idea why this situation occurs,
Thanks for your reading, and hope get your reply.