How to rotate proxies in Python (requests and aiohttp)

import asyncio, itertools, random
import requests, aiohttp
from aiohttp_socks import ProxyConnector  # pip install aiohttp-socks

USER, PASS, HOST = "USER", "PASS", "proxy.s4m.online"
POOL = [
    f"socks5h://{USER}:{PASS}@{HOST}:1080",
    f"http://{USER}:{PASS}@{HOST}:3128",
    # add more endpoints/ports here to widen the pool
]

# ---------- Synchronous: requests + round-robin + retirement ----------
class Rotator:
    def __init__(self, pool):
        self.alive = list(pool)
        self.fails = {p: 0 for p in pool}
        self._cycle = itertools.cycle(self.alive)

    def pick(self):
        return next(self._cycle)

    def retire(self, proxy):
        self.fails[proxy] += 1
        if self.fails[proxy] >= 3 and proxy in self.alive:
            self.alive.remove(proxy)
            self._cycle = itertools.cycle(self.alive or POOL)

def get(url, rot, retries=4):
    for _ in range(retries):
        proxy = rot.pick()
        try:
            r = requests.get(url, proxies={"http": proxy, "https": proxy},
                             timeout=(5, 20))
            r.raise_for_status()
            return r
        except requests.RequestException:
            rot.retire(proxy)
    raise SystemExit("pool exhausted")

rot = Rotator(POOL)
print(get("https://api.ipify.org", rot).text)

# ---------- Async: aiohttp, one connector per proxy ----------
async def fetch(url, proxy):
    connector = ProxyConnector.from_url(proxy)
    async with aiohttp.ClientSession(connector=connector) as s:
        async with s.get(url, timeout=aiohttp.ClientTimeout(total=25)) as r:
            return await r.text()

async def main():
    tasks = [fetch("https://api.ipify.org", random.choice(POOL))
             for _ in range(5)]
    for ip in await asyncio.gather(*tasks, return_exceptions=True):
        print(ip)

asyncio.run(main())