[CI] Try introducing isort. (#3495)

tests/spec_decode/utils.py

@@ -1,17 +1,19 @@
-import torch
-from typing import List, Optional, Dict, Iterable, Union
+from dataclasses import dataclass, fields
+from itertools import count
+from typing import Dict, Iterable, List, Optional, Union
 from unittest.mock import MagicMock
 
-from vllm.worker.worker import Worker
-from vllm.utils import get_distributed_init_method, get_ip, get_open_port
+import torch
+
 from vllm.engine.arg_utils import EngineArgs
-from vllm.sequence import (Logprob, SequenceGroupMetadata, SequenceData,
-                           SamplerOutput, SequenceGroupOutput, SequenceOutput)
-from vllm.sampling_params import SamplingParams
-from vllm.worker.cache_engine import CacheEngine
 from vllm.model_executor.utils import set_random_seed
-from itertools import count
-from dataclasses import dataclass, fields
+from vllm.sampling_params import SamplingParams
+from vllm.sequence import (Logprob, SamplerOutput, SequenceData,
+                           SequenceGroupMetadata, SequenceGroupOutput,
+                           SequenceOutput)
+from vllm.utils import get_distributed_init_method, get_ip, get_open_port
+from vllm.worker.cache_engine import CacheEngine
+from vllm.worker.worker import Worker
 
 
 @dataclass