fromtyping_extensions import ParamSpec ImportError：无法从“typing_extensions”导入名称“ParamSpec”

我正在研究 FastAPI 并发生了这个错误。

from fastapi import FastAPI
import uvicorn
app = FastAPI()

@app.get("/ping")
async def ping():
    return "Hello, I am alive"

if __name__ == "__main__":
    uvicorn.run(app, host='localhost', port=8000)

Traceback (most recent call last):
  File "D:/own_thesis/training/for_api.py", line 2, in <module>
    from fastapi import FastAPI
  File "C:\Users\USER\AppData\Local\Programs\Python\Python37\lib\site-packages\fastapi\__init__.py", line 7, in <module>
    from .applications import FastAPI as FastAPI
  File "C:\Users\USER\AppData\Local\Programs\Python\Python37\lib\site-packages\fastapi\applications.py", line 15, in <module>
    from fastapi import routing
  File "C:\Users\USER\AppData\Local\Programs\Python\Python37\lib\site-packages\fastapi\routing.py", line 22, in <module>
    from fastapi.datastructures import Default, DefaultPlaceholder
  File "C:\Users\USER\AppData\Local\Programs\Python\Python37\lib\site-packages\fastapi\datastructures.py", line 3, in <module>
    from starlette.datastructures import URL as URL  # noqa: F401
  File "C:\Users\USER\AppData\Local\Programs\Python\Python37\lib\site-packages\starlette\datastructures.py", line 7, in <module>
    from starlette.concurrency import run_in_threadpool
  File "C:\Users\USER\AppData\Local\Programs\Python\Python37\lib\site-packages\starlette\concurrency.py", line 11, in <module>
    from typing_extensions import ParamSpec
ImportError: cannot import name 'ParamSpec' from 'typing_extensions' (C:\Users\USER\AppData\Local\Programs\Python\Python37\lib\site-packages\typing_extensions.py)

只需将 @arunppsg 的回复作为一个带有小拼写错误更正的答案即可：您只需要运行

pip uninstall typing_extensions
pip uninstall fastapi
pip install --no-cache fastapi

问题就消失了。

小错别字更正在pip uninstall typing_extensions（末尾有 s）。谢谢@arunppsg，我无法对你的评论发表评论，因为我仍然没有 50 点声誉，并决定将其作为答案。如果您将评论转换为答案，我们很乐意将其删除。