https://travis-ci.org/github/MarcoFalke/btc_nightly/jobs/680655419#L412
{
    std::string wallet_name;
    if (GetWalletNameFromJSONRPCRequest(request, wallet_name)) {
        std::shared_ptr<CWallet> pwallet = GetWallet(wallet_name);
        if (!pwallet) throw JSONRPCError(RPC_WALLET_NOT_FOUND, "Requested wallet does not exist or is not loaded");
        return pwallet;
    }
    std::vector<std::shared_ptr<CWallet>> wallets = GetWallets();
    return wallets.size() == 1 || (request.fHelp && wallets.size() > 0) ? wallets[0] : nullptr;
}
bool EnsureWalletIsAvailable(const CWallet* pwallet, bool avoidException)
{
    if (pwallet) return true;
    if (avoidException) return false;
    if (!HasWallets()) {
        throw JSONRPCError(
            RPC_METHOD_NOT_FOUND, "Method not found (wallet method is disabled because no wallet is loaded)");
    }
    throw JSONRPCError(RPC_WALLET_NOT_SPECIFIED,
        "Wallet file not specified (must request wallet RPC through /wallet/<filename> uri-path).");
}
void EnsureWalletIsUnlocked(const CWallet* pwallet)