fix linting

Signed-off-by: Nick Hill <nhill@redhat.com>

Author: njhill

vllm/v1/engine/core.py

@@ -231,7 +231,8 @@ def step(self) -> tuple[EngineCoreOutputs, bool]:
         engine_core_outputs = self.scheduler.update_from_output(
             scheduler_output, model_output)  # type: ignore
 
-        return engine_core_outputs, scheduler_output.total_num_scheduled_tokens > 0
+        return (engine_core_outputs,
+                scheduler_output.total_num_scheduled_tokens > 0)
 
     def step_with_batch_queue(
             self) -> tuple[Optional[EngineCoreOutputs], bool]: