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 <consensus/amount.h>
#include <consensus/params.h>
#include <consensus/validation.h>
#include <core_io.h>
#include <deploymentinfo.h>
#include <deploymentstatus.h>
#include <fs.h>
#include <hash.h>
#include <index/blockfilterindex.h>
#include <index/coinstatsindex.h>
#include <kernel/coinstats.h>
#include <logging/timer.h>
#include <net.h>
#include <net_processing.h>
#include <node/blockstorage.h>
#include <node/context.h>
#include <node/utxo_snapshot.h>
#include <primitives/transaction.h>
#include <rpc/server.h>
#include <rpc/server_util.h>
#include <rpc/util.h>
#include <script/descriptor.h>
#include <streams.h>
#include <sync.h>
#include <txdb.h>
#include <txmempool.h>
#include <undo.h>
#include <univalue.h>