How to call the data loader inside pl.LightningModule?

[KinWaiCheuk]

My scheduler takes the total number of steps len(train_loader)*epochs as one of its arguments.
I know inside the pl.LightningModule, I can get the number of epochs via self.trainer.max_epochs.

But how to get the data_loader?
I have tried self.trainer.train_dataloaders, self.train_dataloaders, but it does not return me the data loader I want.