diff --git a/examples/by_feature/megatron_lm_gpt_pretraining.py b/examples/by_feature/megatron_lm_gpt_pretraining.py
index b0e1b33700f..eb7efb3a79e 100644
--- a/examples/by_feature/megatron_lm_gpt_pretraining.py
+++ b/examples/by_feature/megatron_lm_gpt_pretraining.py
@@ -405,7 +405,7 @@ def tokenize_function(examples):
                 f"The tokenizer picked seems to have a very large `model_max_length` ({tokenizer.model_max_length}). "
                 "Picking 1024 instead. You can change that default value by passing --block_size xxx."
             )
-        block_size = 1024
+            block_size = 1024
     else:
         if args.block_size > tokenizer.model_max_length:
             logger.warning(