Get last month's spending by category

from collections import Counter
from datetime import date, timedelta
from clickruntime import on_trigger, credentials, http, notify

PLAID = "https://production.plaid.com"

def plaid(path, **body):
    auth = {"client_id": credentials.secret("PLAID_CLIENT_ID"), "secret": credentials.secret("PLAID_SECRET"),
            "access_token": credentials.secret("PLAID_ACCESS_TOKEN")}
    resp = http.post(f"{PLAID}{path}", json={**auth, **body})
    resp.raise_for_status()
    return resp.json()

SKIP = {"TRANSFER_IN", "TRANSFER_OUT", "LOAN_PAYMENTS"}

@on_trigger
def run(event):
    end = date.today().replace(day=1) - timedelta(days=1)
    txns, offset = [], 0
    while True:
        page = plaid("/transactions/get", start_date=end.replace(day=1).isoformat(), end_date=end.isoformat(),
                     options={"count": 500, "offset": offset})
        txns += page["transactions"]
        offset = len(txns)
        if offset >= page["total_transactions"]:
            break
    spend = [t for t in txns if t["amount"] > 0 and t["personal_finance_category"]["primary"] not in SKIP]
    cats = Counter(); merchants = Counter()
    for t in spend:
        cats[t["personal_finance_category"]["primary"]] += t["amount"]
        merchants[t.get("merchant_name") or t["name"]] += t["amount"]
    body = "\n".join(f"{c}: {v:,.2f}" for c, v in cats.most_common())
    body += "\n\nTop merchants:\n" + "\n".join(f"{m}: {v:,.2f}" for m, v in merchants.most_common(5))
    notify.email_me(f"Spending in {end:%B}: {sum(cats.values()):,.2f}", body)
    return dict(cats)