Update app.py

app.py

@@ -17,11 +17,11 @@ import ffmpeg
 def process_video(video_file, youtube_url, language_choice):
     if language_choice == None:
         return None, "Select a language to translate to."
-    elif video_file == None and youtube_url == None:
+    elif video_file == None and youtube_url == "":
         return None, "Upload either a video or a valid youtube URL."        
-    elif video_file != None and youtube_url != None:
+    elif video_file != None and youtube_url != "":
         return None, "Videos contradict. Delete either the uploaded video or youtube URL."
-    elif video_file == None and youtube_url != None:
+    elif video_file == None and youtube_url != "":
         yt = YouTube(youtube_url)
         yt.streams.filter(progressive=True, file_extension='mp4').first().download(filename="original.mp4")
         video_file = "original.mp4"