def training_step(self, batch, batch_index):
    ((x0, x1), _, _) = batch
    z0 = self.forward(x0)
    z1 = self.forward(x1)
    loss = self.criterion(z0, z1)
    self.log('train_loss_ssl', loss)
    return loss
def training_step(self, batch, batch_index):
    ((x0, x1), _, _) = batch
    z0 = self.forward(x0)
    z1 = self.forward(x1)
    loss = self.criterion(z0, z1)
    self.log('train_loss_ssl', loss)
    return loss