backward callback does not work on pytorch-lightning version 1.0.0rc3
In pytorch-lightning version 0.10 the following code works well. However in pytorch-lightning version 1.0.0rc3, the code does not work
and gives the following error:
TypeError: backward() missing 1 required positional argument: 'optimizer_idx'
Code sample
def configure_optimizers(self):
      optimizer = optim.Adam(self.parameters(), lr=self.hparams.lr)
      return optimizer

def backward(self, trainer, loss, optimizer, optimizer_idx):
        loss.backward(retain_graph=True)