Block disposable email in AWS Cognito

The code

# lambda_function.py
import json
import os
import urllib.request

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

def is_disposable(email: str) -> bool:
    try:
        req = urllib.request.Request(
            PIISEND_URL,
            data=json.dumps({"email": email}).encode(),
            headers={
                "Authorization": f"Bearer {os.environ['PIISEND_API_KEY']}",
                "Content-Type": "application/json",
            },
            method="POST",
        )
        with urllib.request.urlopen(req, timeout=5) as resp:
            data = json.loads(resp.read())
            return data.get("signals", {}).get("disposable") is True
    except Exception:
        return False  # fail open

def lambda_handler(event, context):
    email = event["request"]["userAttributes"].get("email", "")
    if email and is_disposable(email):
        raise Exception("Please use a permanent email address.")
    return event