[CI] Try introducing isort. (#3495)

vllm/entrypoints/openai/api_server.py

@@ -1,28 +1,27 @@
 import asyncio
-from contextlib import asynccontextmanager
-import os
 import importlib
 import inspect
+import os
+from contextlib import asynccontextmanager
+from http import HTTPStatus
 
-from prometheus_client import make_asgi_app
 import fastapi
 import uvicorn
-from http import HTTPStatus
 from fastapi import Request
 from fastapi.exceptions import RequestValidationError
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import JSONResponse, StreamingResponse, Response
+from fastapi.responses import JSONResponse, Response, StreamingResponse
+from prometheus_client import make_asgi_app
 
 import vllm
 from vllm.engine.arg_utils import AsyncEngineArgs
 from vllm.engine.async_llm_engine import AsyncLLMEngine
-from vllm.entrypoints.openai.protocol import (CompletionRequest,
-                                              ChatCompletionRequest,
-                                              ErrorResponse)
-from vllm.logger import init_logger
 from vllm.entrypoints.openai.cli_args import make_arg_parser
+from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
+                                              CompletionRequest, ErrorResponse)
 from vllm.entrypoints.openai.serving_chat import OpenAIServingChat
 from vllm.entrypoints.openai.serving_completion import OpenAIServingCompletion
+from vllm.logger import init_logger
 
 TIMEOUT_KEEP_ALIVE = 5  # seconds