[Python] Why FastAPI cannot parse UUID by pattern while Regex101 can?

I have some FastAPI application:

from typing import Annotated

import uvicorn
from fastapi import FastAPI, Query
from pydantic import constr

app = FastAPI()


@app.get("search")
async def search(
partner_ids: Annotated[
constr(pattern="((^|[,])[0-9a-fA-F]{8}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{12})+"),
Query(),
] = "ca930bc7-f4cf-4b10-9c6f-7db13b6ab4f0",
):
pass


if __name__ == "__main__":
uvicorn.run("uuid_list:app", reload=True, port=8004)


The problem with it is validation of partner_ids does not work:



At the same time regex101 finds uuid:



What's wrong with FastAPI?

Upd. The regex is for comma separated list of uuids.

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