Fixed `submission_file == None`

app.py

@@ -33,11 +33,10 @@ SUBMISSION_INPUTS = dict.fromkeys((
 def on_submit_pressed():
     return gr.update(value='Processing submission...', interactive=False)
 
-
-def validate_submission_inputs(**kwargs):
-    if SUBMISSION_INPUTS - set(kwargs) != set():
+def validate_submission_inputs(**inputs):
+    if any(key for key, value in inputs.items() if value in (None, "")):
         raise ValueError('Please fill in all fields')
-    if not os.path.exists(kwargs["submission_file"]):
+    if not os.path.exists(inputs["submission_file"]):
         raise ValueError('File does not exist')
 
 def process_submission(*inputs):