[Frontend] Add FlexibleArgumentParser to support both underscore and dash in names (#5718)

vllm/entrypoints/openai/run_batch.py

@@ -1,4 +1,3 @@
-import argparse
 import asyncio
 import sys
 from io import StringIO
@@ -16,14 +15,14 @@ from vllm.entrypoints.openai.protocol import (BatchRequestInput,
 from vllm.entrypoints.openai.serving_chat import OpenAIServingChat
 from vllm.logger import init_logger
 from vllm.usage.usage_lib import UsageContext
-from vllm.utils import random_uuid
+from vllm.utils import FlexibleArgumentParser, random_uuid
 from vllm.version import __version__ as VLLM_VERSION
 
 logger = init_logger(__name__)
 
 
 def parse_args():
-    parser = argparse.ArgumentParser(
+    parser = FlexibleArgumentParser(
         description="vLLM OpenAI-Compatible batch runner.")
     parser.add_argument(
         "-i",