clarify assert

src/client/remote_generation.py

@@ -68,12 +68,12 @@ class RemoteGenerationMixin:
         pad_token_id = pad_token_id if pad_token_id is not None else self.config.pad_token_id
         eos_token_id = eos_token_id if eos_token_id is not None else self.config.eos_token_id
 
+        assert (max_length is None) != (max_new_tokens is None), "please set max_length or max_new_tokens (not both)"
         if max_length is not None and max_new_tokens is None:
             max_new_tokens = max_length - prefix_length
             assert max_new_tokens > 0, f"Provided max_length is less than prefix size: {max_length} < {inputs.size(1)}"
         elif max_length is None and max_new_tokens is not None:
             max_length = prefix_length + max_new_tokens
-        assert max_length is not None and max_new_tokens is not None
 
         if inputs is None:
             assert bos_token_id is not None, "You have to provide a bos_token_id if you do not provide inputs"