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.
{
    return RPCHelpMan{"getblockhash",
                "\nReturns hash of block in best-block-chain at height provided.\n",
                {
                    {"height", RPCArg::Type::NUM, RPCArg::Optional::NO, "The height index"},
                },
                RPCResult{
                    RPCResult::Type::STR_HEX, "", "The block hash"},
                RPCExamples{
                    HelpExampleCli("getblockhash", "1000")
            + HelpExampleRpc("getblockhash", "1000")
                },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    ChainstateManager& chainman = EnsureAnyChainman(request.context);
    LOCK(cs_main);
    const CChain& active_chain = chainman.ActiveChain();
    int nHeight = request.params[0].getInt<int>();
    if (nHeight < 0 || nHeight > active_chain.Height())
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Block height out of range");
    const CBlockIndex* pblockindex = active_chain[nHeight];
    return pblockindex->GetBlockHash().GetHex();
},
    };
}
static RPCHelpMan getblockheader()