human
I wrote the below code

    if (args is None):
        return {}
    search_offset = int(args.get('search_offset', 0))
    def _parse_timestamp(timestamp):
        if (not timestamp):
            return None
        try:
            iso_timestamp = timeutils.parse_isotime(timestamp)
            iso_timestamp = iso_timestamp.replace(tzinfo=None)
        except ValueError:
            raise wsme.exc.InvalidInput('timestamp', timestamp, 'invalid    timestamp    format')
        return iso_timestamp
    start_timestamp = _parse_timestamp(args.get('start_timestamp'))
    end_timestamp = _parse_timestamp(args.get('end_timestamp'))
    start_timestamp = ((start_timestamp - datetime.timedelta(minutes=search_offset)) if start_timestamp else None)
    end_timestamp = ((end_timestamp + datetime.timedelta(minutes=search_offset)) if end_timestamp else None)
    return {'start_timestamp': start_timestamp, 'end_timestamp': end_timestamp, 'start_timestamp_op': args.get('start_timestamp_op'), 'end_timestamp_op': args.get('end_timestamp_op')}

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def _get_query_timestamps(args=None):