minor update for play and load function

deprl/play.py

@@ -311,6 +311,7 @@ def play(
     config, checkpoint_path, _ = load_checkpoint(checkpoint_path, checkpoint)
 
     # Get important info from config
+    assert config is not None
     header = header or config["tonic"]["header"]
     agent = agent or config["tonic"]["agent"]
     environment = environment or config["tonic"]["test_environment"]

deprl/utils/load_utils.py

@@ -44,6 +44,7 @@ def load_checkpoint(checkpoint_path, checkpoint="last"):
     Checkpoint loading for main() function.
     """
     if not os.path.isdir(checkpoint_path):
+        logger.log(f"Checkpoint path is not valid: {checkpoint_path}")
         return None, None, None
 
     path = (