Fix bug in error output

app.py

@@ -10,7 +10,7 @@ emb_size = 128
 inp_len = 16
 
 def train(data: str, message: str):
-    if "→" not in data and "\n" not in data:
+    if "→" not in data or "\n" not in data:
         return "Dataset should be like:\nquestion→answer\nquestion→answer\netc."
     dset, responses = todset(data)
     resps_len = len(responses)