def collect_app_usage(days_back):
    server = 'localhost'
    log_type = 'Security'
    hand = win32evtlog.OpenEventLog(server, log_type)
    flags = win32evtlog.EVENTLOG_BACKWARDS_READ | win32evtlog.EVENTLOG_SEQUENTIAL_READ

    usage_records = []
    cutoff_date = datetime.datetime.now() - datetime.timedelta(days=days_back)

    events = True
    while events:
        events = win32evtlog.ReadEventLog(hand, flags, 0)
        for ev_obj in events:
            event_time = ev_obj.TimeGenerated