Mock OA: incident digest

def incident_digest(records: list[str], k: int) -> dict:
    import heapq
    from collections import Counter
    from datetime import datetime
    parsed = []
    users = Counter()
    for record in records:
        timestamp, user, latency = record.split('|')
        parsed.append((datetime.fromisoformat(timestamp), user, int(latency)))
        users[user] += 1
    busiest = min(users, key=lambda user: (-users[user], user))
    latencies = heapq.nlargest(k, (row[2] for row in parsed))
    duration = int((max(row[0] for row in parsed) - min(row[0] for row in parsed)).total_seconds())
    return {'busiest_user': busiest, 'top_latencies': latencies, 'duration_seconds': duration}