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.
{RPCResult::Type::NUM, "outs", true, "The number of outputs"},
                {RPCResult::Type::NUM, "subsidy", true, "The block subsidy"},
                {RPCResult::Type::NUM, "swtotal_size", true, "Total size of all segwit transactions"},
                {RPCResult::Type::NUM, "swtotal_weight", true, "Total weight of all segwit transactions"},
                {RPCResult::Type::NUM, "swtxs", true, "The number of segwit transactions"},
                {RPCResult::Type::NUM, "time", true, "The block time"},
                {RPCResult::Type::NUM, "total_out", true, "Total amount in all outputs (excluding coinbase and thus reward [ie subsidy + totalfee])"},
                {RPCResult::Type::NUM, "total_size", true, "Total size of all non-coinbase transactions"},
                {RPCResult::Type::NUM, "total_weight", true, "Total weight of all non-coinbase transactions"},
                {RPCResult::Type::NUM, "totalfee", true, "The fee total"},
                {RPCResult::Type::NUM, "txs", true, "The number of transactions (including coinbase)"},
                {RPCResult::Type::NUM, "utxo_increase", true, "The increase/decrease in the number of unspent outputs"},
                {RPCResult::Type::NUM, "utxo_size_inc", true, "The increase/decrease in size for the utxo index (not discounting op_return and similar)"},
            }},
                RPCExamples{
                    HelpExampleCli("getblockstats", R"('"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09"' '["minfeerate","avgfeerate"]')") +
                    HelpExampleCli("getblockstats", R"(1000 '["minfeerate","avgfeerate"]')") +
                    HelpExampleRpc("getblockstats", R"("00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09", ["minfeerate","avgfeerate"])") +
                    HelpExampleRpc("getblockstats", R"(1000, ["minfeerate","avgfeerate"])")
                },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    ChainstateManager& chainman = EnsureAnyChainman(request.context);
    LOCK(cs_main);
    const CBlockIndex& pindex{*CHECK_NONFATAL(ParseHashOrHeight(request.params[0], chainman))};
    std::set<std::string> stats;
    if (!request.params[1].isNull()) {
        const UniValue stats_univalue = request.params[1].get_array();
        for (unsigned int i = 0; i < stats_univalue.size(); i++) {
            const std::string stat = stats_univalue[i].get_str();