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.
{
    
    CRITICAL = 2,
    
    LARGE = 1,
    OK = 0
};
/**
 * Chainstate stores and provides an API to update our local knowledge of the
 * current best chain.
 *
 * Eventually, the API here is targeted at being exposed externally as a
 * consumable libconsensus library, so any functions added must only call
 * other class member functions, pure functions in other parts of the consensus
 * library, callbacks via the validation interface, or read/write-to-disk
 * functions (eventually this will also be via callbacks).
 *
 * Anything that is contingent on the current tip of the chain is stored here,
 * whereas block information and metadata independent of the current tip is
 * kept in `BlockManager`.
 */
class Chainstate