[NFC] polish colossalai/fx/tracer/_tracer_utils.py (#3323)

* [NFC] polish colossalai/engine/schedule/_pipeline_schedule.py code style

* [NFC] polish colossalai/fx/tracer/_tracer_utils.py  code style

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Co-authored-by: Qianran Ma <qianranm@luchentech.com>

colossalai/fx/tracer/_tracer_utils.py

-from typing import List, Union, Any
-from ..proxy import ColoProxy, ColoAttribute
+from typing import Any, List, Union
+
 import torch
+
+from ..proxy import ColoAttribute, ColoProxy
 from .meta_patch import meta_patched_function, meta_patched_module
 
 __all__ = ['is_element_in_list', 'extract_meta']