code: def on_batch_end(self, batch_info):
          
          if self.settings.stream_lr:
              iteration_idx = (
                      float(batch_info.epoch_number) +
                      float(batch_info.batch_number) / batch_info.batches_per_epoch
              )
              
              lr = batch_info.optimizer.param_groups[-1]['lr']
  
              metrics_df = pd.DataFrame([lr], index=[iteration_idx], columns=['lr'])
  
              visdom_append_metrics(
                  self.vis,
                  metrics_df,
                  first_epoch=(batch_info.epoch_number == 1) and (batch_info.batch_number == 0)
              )
docs: Stream LR to visdom