def get_redact_list(item):
    """
    Get the redaction list, ensuring that the images and metadata
    dictionaries exist.

    :param item: a Girder item.
    :returns: the redactList object.
    """
    redactList = item.get('meta', {}).get('redactList', {})
    for cat in {'images', 'metadata'}:
        redactList.setdefault(cat, {})
        for key in list(redactList[cat]):
            if not isinstance(redactList[cat][key], dict):
                redactList[cat][key] = {'value': redactList[cat][key]}
    return redactList