Find out when a key Amplitude event stops firing

import json
from datetime import date, datetime, timedelta, timezone
from clickruntime import on_trigger, credentials, http, notify

def amp(path, **params):
    auth = (credentials.secret("AMPLITUDE_API_KEY"), credentials.secret("AMPLITUDE_SECRET_KEY"))
    resp = http.get(f"https://amplitude.com/api/2/{path}", auth=auth, params=params)
    resp.raise_for_status()
    return resp.json()["data"]

@on_trigger
def run(event):
    now = datetime.now(timezone.utc)
    start = (now - timedelta(days=7)).strftime("%Y%m%dT%H")
    data = amp("events/segmentation", e=json.dumps({"event_type": "Purchase"}),
               start=start, end=now.strftime("%Y%m%dT%H"), i=-3600000, m="totals")
    hours = dict(zip(data["xValues"], data["series"][0]))
    last_hour = (now - timedelta(hours=1)).strftime("%Y-%m-%dT%H:00:00")
    count = hours.get(last_hour, 0)
    usual = [v for k, v in hours.items() if k[11:13] == last_hour[11:13] and k != last_hour]
    avg = sum(usual) / len(usual) if usual else 0
    if count == 0 or count < avg / 2:
        notify.slack(f"Purchase events low: {count} in the hour from {last_hour[11:16]} UTC (usual {avg:.0f}).",
                     channel="#product")
    return {"count": count, "usual": round(avg, 1)}