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.
#include <chainparams.h>
#include <coins.h>
#include <crypto/muhash.h>
#include <index/coinstatsindex.h>
#include <kernel/coinstats.h>
#include <node/blockstorage.h>
#include <serialize.h>
#include <txdb.h>
#include <undo.h>
#include <util/system.h>
#include <validation.h>
using kernel::CCoinsStats;
using kernel::GetBogoSize;
using kernel::TxOutSer;
using node::ReadBlockFromDisk;
using node::UndoReadFromDisk;
static constexpr uint8_t DB_BLOCK_HASH{'s'};
static constexpr uint8_t DB_BLOCK_HEIGHT{'t'};
static constexpr uint8_t DB_MUHASH{'M'};
namespace {
struct DBVal {
    uint256 muhash;
    uint64_t transaction_output_count;
    uint64_t bogo_size;
    CAmount total_amount;
    CAmount total_subsidy;