Use lightning with dgl
def train_dataloader(self):
        return DataLoader(self.train_dataset,
                          batch_size=self.hparams.batch_size,
                          shuffle=True,
                          num_workers=4,
                          collate_fn=self.batcher)

I use collate_fn to batch dgl graphs, but when I training model, trigger this warning:
DGLWarning: DGLGraph.__len__ is deprecated.Please directly call DGLGraph.number_of_nodes.
How tor fix it ?