How to use the pgspecial.namedqueries.NamedQueries.instance.usage function in pgspecial

def list_named_queries(verbose):
    """List of all named queries.
    Returns (title, rows, headers, status)"""
    if not verbose:
        rows = [[r] for r in NamedQueries.instance.list()]
        headers = ["Name"]
    else:
        headers = ["Name", "Query"]
        rows = [[r, NamedQueries.instance.get(r)]
                for r in NamedQueries.instance.list()]

    if not rows:
        status = NamedQueries.instance.usage
    else:
        status = ''
    return [('', rows, headers, status)]

def save_named_query(pattern, **_):
    """Save a new named query.
    Returns (title, rows, headers, status)"""

    usage = 'Syntax: \\ns name query.\n\n' + NamedQueries.instance.usage
    if not pattern:
        return [(None, None, None, usage)]

    name, _, query = pattern.partition(' ')

    # If either name or query is missing then print the usage and complain.
    if (not name) or (not query):
        return [(None, None, None,
            usage + 'Err: Both name and query are required.')]

    NamedQueries.instance.save(name, query)
    return [(None, None, None, "Saved.")]