def make_entry(tag, subtag, cachedata, timestamp):
    """Cache entries are a dictionary:
        { "tag" : ..., "subtag" : ..., "cachedata" : ..., "timestamp" : ... }
       where 'cachedata' is a local file path,
             'timestamp' is in milliseconds
    """
    return {'tag': tag, 'subtag': subtag, 'cachedata': cachedata,
        'timestamp': timestamp}
