Update all changes

app.py

@@ -7,7 +7,11 @@ import tempfile
 import shutil
 import os
 
-os.system("python download_nltk_resources.py")
+import nltk
+try:
+    nltk.data.find("tokenizers/punkt")
+except LookupError:
+    nltk.download("punkt")
 
 def run_analysis(db_file, isbn, languages):
     if not isbn.strip():