https://travis-ci.org/github/bitcoin/bitcoin/jobs/680452476#L6107
{
    return RPCHelpMan{"listlabels",
                "\nReturns the list of all labels, or labels that are assigned to addresses with a specific purpose.\n",
                {
                    {"purpose", RPCArg::Type::STR, RPCArg::Optional::OMITTED_NAMED_ARG, "Address purpose to list labels for ('send','receive'). An empty string is the same as not providing this argument."},
                },
                RPCResult{
                    RPCResult::Type::ARR, "", "",
                    {
                        {RPCResult::Type::STR, "label", "Label name"},
                    }
                },
                RPCExamples{
            "\nList all labels\n"
            + HelpExampleCli("listlabels", "") +
            "\nList labels that have receiving addresses\n"
            + HelpExampleCli("listlabels", "receive") +
            "\nList labels that have sending addresses\n"
            + HelpExampleCli("listlabels", "send") +