Block disposable email in FastAPI

The code

# services/disposable.py
import os
import httpx

PIISEND_URL = "https://api.piisend.com/api/v1/intelligence/email"

async def is_disposable_email(email: str) -> bool:
    try:
        async with httpx.AsyncClient(timeout=5.0) as client:
            r = await client.post(
                PIISEND_URL,
                headers={
                    "Authorization": f"Bearer {os.environ['PIISEND_API_KEY']}",
                    "Content-Type": "application/json",
                },
                json={"email": email},
            )
        if not r.is_success:
            return False
        return r.json().get("signals", {}).get("disposable") is True
    except httpx.HTTPError:
        return False

# routes/auth.py
from fastapi import APIRouter, HTTPException
from .services.disposable import is_disposable_email

router = APIRouter()

@router.post("/signup")
async def signup(email: str, password: str):
    if await is_disposable_email(email):
        raise HTTPException(400, "Please use a permanent email address.")
    # ...create user