Update src/transformers/generation/utils.py

Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>

Author: gante

src/transformers/generation/utils.py

@@ -4426,7 +4426,7 @@ def assisted_decoding(
                 The sequence used as a prompt for the generation.
             candidate_generator (`CandidateGenerator`, *optional*):
                 A derived instance of [`CandidateGenerator`] that defines how candidate sequences are generated. For
-                more information, the documentation of [`CandidateGenerator`] should be read.
+                more information, the documentation of [`CandidateGenerator`] should be read. Only one of `assistant_model` or `candidate_generator` should be passed as input to this function.
             assistant_model (`PreTrainedModel`, *optional*):
                 An assistant model that can be used to accelerate generation. The assistant model must have the exact
                 same tokenizer. The acceleration is achieved when forecasting candidate tokens with the assistent model