Update app.py

app.py

@@ -7,6 +7,7 @@ Based on this example: https://github.com/neuml/txtai/blob/master/examples/workf
 import os
 import re
 
+import nltk
 import yaml
 
 import pandas as pd
@@ -376,6 +377,11 @@ def create():
 if __name__ == "__main__":
     os.environ["TOKENIZERS_PARALLELISM"] = "false"
 
+    try:
+        nltk.sent_tokenize("This is a test. Split")
+    except:
+        nltk.download("punkt")
+
     # Create and run application
     app = create()
     app.run()