error out for empty audio

app.py

@@ -28,6 +28,8 @@ def format_as_transcription(raw_segments, with_timestamps=False):
 
 
 def transcribe(file_upload, with_timestamps):
+    if file_upload is None:
+        raise gr.Error("No audio file submitted! Please upload an audio file before submitting your request.")
     raw_segments = pipe(file_upload)
     transcription = format_as_transcription(raw_segments, with_timestamps=with_timestamps)
     return transcription