question: How to monitor tensorboard logged scalar in modelcheckpoint?
context: If I save scalar log like this,
  self.logger.experiment.add_scalars(‘loss/nll’, {‘train’: trainloss, ‘valid’: validloss})
  
  How to monitor valid loss in Modelcheckpoint?
answer: you need to call it with self.log instead (we automate the rest for you), so that we are aware of you logging it :)