Fix: #2674 (#2683)

* Set resume flag to false

* Check existance of val dataset

utils/wandb_logging/wandb_utils.py

@@ -158,7 +158,7 @@ class WandbLogger():
         return data_dict
 
     def download_dataset_artifact(self, path, alias):
-        if path.startswith(WANDB_ARTIFACT_PREFIX):
+        if path and path.startswith(WANDB_ARTIFACT_PREFIX):
             dataset_artifact = wandb.use_artifact(remove_prefix(path, WANDB_ARTIFACT_PREFIX) + ":" + alias)
             assert dataset_artifact is not None, "'Error: W&B dataset artifact doesn\'t exist'"
             datadir = dataset_artifact.download()