Update observer to detect invalid dataset name

Author: Matheus-Gr

learning_orchestra_client/observer.py

@@ -40,6 +40,10 @@ def observe_processing(self, pretty_response=False):
         metadata_query = {"_id": 0}
         dataset_metadata = dataset_collection.find_one(metadata_query)
 
+        if dataset_metadata is None:
+            print("Dataset name invalid")
+            exit()
+
         if dataset_metadata["finished"]:
             return dataset_metadata