Update app.py

app.py

@@ -1,8 +1,13 @@
 import os
 
 def fetch_transcript(url, name):
-    os.system(f"youtube-dl --write-auto-sub --skip-download --sub-format txt {url} -o {name}.txt")
-    return f"{name}.txt"
+    transcript_filename = f"{name}.txt"
+    os.system(f"youtube-dl --write-auto-sub --skip-download --sub-format txt {url} -o {transcript_filename}")
+    
+    if os.path.exists(transcript_filename):
+        return transcript_filename
+    else:
+        raise FileNotFoundError(f"Transcript file '{transcript_filename}' could not be found.")
 
 import gradio as gr