the command "bitcoin-cli getblockstats 0000000000000000000c61ff8f761ce509fc8901d3c22d61fec89637042ea2ba" does not work.

It displays "error: Error parsing JSON:0000000000000000000c61ff8f761ce509fc8901d3c22d61fec89637042ea2ba"

but it should display the block stats like the documentation says.

also bitcoin-cli getblockstats 0 does not work. block number must be at least 1 to work. But blocks start at 0.

tested with 0.20.1 on freebsd, another user on IRC acknowledged the problem.
},
    };
}
static RPCHelpMan getchaintxstats()
{
    return RPCHelpMan{"getchaintxstats",
                "\nCompute statistics about the total number and rate of transactions in the chain.\n",
                {
                    {"nblocks", RPCArg::Type::NUM, RPCArg::DefaultHint{"one month"}, "Size of the window in number of blocks"},
                    {"blockhash", RPCArg::Type::STR_HEX, RPCArg::DefaultHint{"chain tip"}, "The hash of the block that ends the window."},
                },
                RPCResult{
                    RPCResult::Type::OBJ, "", "",
                    {
                        {RPCResult::Type::NUM_TIME, "time", "The timestamp for the final block in the window, expressed in " + UNIX_EPOCH_TIME},
                        {RPCResult::Type::NUM, "txcount", "The total number of transactions in the chain up to that point"},
                        {RPCResult::Type::STR_HEX, "window_final_block_hash", "The hash of the final block in the window"},
                        {RPCResult::Type::NUM, "window_final_block_height", "The height of the final block in the window."},
                        {RPCResult::Type::NUM, "window_block_count", "Size of the window in number of blocks"},
                        {RPCResult::Type::NUM, "window_tx_count", true, "The number of transactions in the window. Only returned if \"window_block_count\" is > 0"},
                        {RPCResult::Type::NUM, "window_interval", true, "The elapsed time in the window in seconds. Only returned if \"window_block_count\" is > 0"},
                        {RPCResult::Type::NUM, "txrate", true, "The average rate of transactions per second in the window. Only returned if \"window_interval\" is > 0"},
                    }},
                RPCExamples{
                    HelpExampleCli("getchaintxstats", "")
            + HelpExampleRpc("getchaintxstats", "2016")
                },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    ChainstateManager& chainman = EnsureAnyChainman(request.context);