[misc] upgrade format to py39 (#7256)

scripts/vllm_infer.py

@@ -52,8 +52,8 @@ def vllm_infer(
     image_max_pixels: int = 768 * 768,
     image_min_pixels: int = 32 * 32,
 ):
-    r"""
-    Performs batch generation using vLLM engine, which supports tensor parallelism.
+    r"""Perform batch generation using vLLM engine, which supports tensor parallelism.
+
     Usage: python vllm_infer.py --model_name_or_path meta-llama/Llama-2-7b-hf --template llama --dataset alpaca_en_demo
     """
     check_version("vllm>=0.4.3,<=0.7.3")