diff --git a/src/transformers/generation/utils.py b/src/transformers/generation/utils.py
index 5e363a1062c..0dcd88eac3b 100644
--- a/src/transformers/generation/utils.py
+++ b/src/transformers/generation/utils.py
@@ -699,7 +699,7 @@ class GenerationMixin:
         elif self.config.model_type in ["whisper"]:
             pass
         # user input but it is empty -> use decoder_start_token_id
-        elif decoder_input_ids.size(-1)==0:
+        elif decoder_input_ids.size(-1) == 0:
             decoder_input_ids = decoder_start_token_id
         # user input but doesn't start with decoder_start_token_id -> prepend decoder_start_token_id (and adjust
         # decoder_attention_mask if provided)