How to replace `set` using python

I'm currently facing a problem where I am giving a thread a reference to a set and I want to be able to replace the set with a mocked database call. I have so far done

import logging
import threading
import time
from typing import Callable

from loguru import logger


class MonitorProduct:

    def __init__(self, term: str, is_alive: Callable[[str], bool]) -> None:
        self.is_alive = is_alive
        self.term = term

    def do_request(self) -> None:
        time.sleep(.1)
        while True:
            logger.info(f'Checking {self.term}')
            if not self.is_alive(self.term):
                logger.info(f'Deleting term from monitoring: "{self.term}"')
                return

            time.sleep(5)


# mocked database
def database_terms() -> set[str]:
    return {
        'hello world',
        'python 3',
        'world',
        'wth',
    }


def database_terms_2() -> set[str]:
    return {
        'what am I doing wrong',
    }


def main() -> None:
    terms: set[str] = set()

    while True:
        db_terms = database_terms()
        diff = db_terms - terms
        terms.symmetric_difference_update(db_terms)

        for url in diff:
            logger.info(f'Starting URL: {url}')
            threading.Thread(
                target=MonitorProduct(url, terms.__contains__).do_request
            ).start()

        time.sleep(2)

        # ----------------------------------------------- #

        db_terms = database_terms_2() 
        diff = db_terms - terms
        terms.symmetric_difference_update(db_terms) # <--- terms should only now contain `what am I doing wrong`

        # Start the new URLS
        for url in diff:
            logger.info(f'Starting URL 2: {url}')
            threading.Thread(
                target=MonitorProduct(url, terms.__contains__).do_request
            ).start()

        time.sleep(10)


if __name__ == '__main__':
    main()

The problem I am now having is that when we do our first db call, it should start threads for each of terms:

{
  'hello world',
  'python 3',
  'world',
  'wth',
}

and as you can see we also send in a terms.__contains__ for each thread.

When we do the second call of db - that set should replace the terms to

{
  'what am I doing wrong',
}

which should end up exiting the four running threads due to:

def do_request(self) -> None:
        time.sleep(.1)
        while True:
            logger.info(f'Checking {self.term}')
            if not self.is_alive(self.term):
                logger.info(f'Deleting term from monitoring: "{self.term}"')
                return

            time.sleep(5)

however the problem is that we cannot replace terms by doing

terms = ... because we are creating a new set and then bidning that set to the variable terms while the thread still has a reference to the old set.

My question is, how can I replace the old terms with updating to the newest set without binding a new set?