s2s: fix LR logging, remove some dead code. (#6205)

examples/lightning_base.py

@@ -58,7 +58,6 @@ class BaseTransformer(pl.LightningModule):
 
         self.hparams = hparams
         self.step_count = 0
-        self.tfmr_ckpts = {}
         self.output_dir = Path(self.hparams.output_dir)
         cache_dir = self.hparams.cache_dir if self.hparams.cache_dir else None
         if config is None:
@@ -99,7 +98,7 @@ class BaseTransformer(pl.LightningModule):
         self.model = self.model_type.from_pretrained(*args, **kwargs)
 
     def configure_optimizers(self):
-        "Prepare optimizer and schedule (linear warmup and decay)"
+        """Prepare optimizer and schedule (linear warmup and decay)"""
         model = self.model
         no_decay = ["bias", "LayerNorm.weight"]
         optimizer_grouped_parameters = [
@@ -159,11 +158,9 @@ class BaseTransformer(pl.LightningModule):
     @pl.utilities.rank_zero_only
     def on_save_checkpoint(self, checkpoint: Dict[str, Any]) -> None:
         save_path = self.output_dir.joinpath("best_tfmr")
-        save_path.mkdir(exist_ok=True)
         self.model.config.save_step = self.step_count
         self.model.save_pretrained(save_path)
         self.tokenizer.save_pretrained(save_path)
-        self.tfmr_ckpts[self.step_count] = save_path
 
     @staticmethod
     def add_model_specific_args(parser, root_dir):
@@ -274,7 +271,6 @@ def add_generic_args(parser, root_dir) -> None:
         default=1,
         help="Number of updates steps to accumulate before performing a backward/update pass.",
     )
-
     parser.add_argument("--seed", type=int, default=42, help="random seed for initialization")