Status Command::explain(OperationContext* opCtx,
                        const string& dbname,
                        const BSONObj& cmdObj,
                        ExplainOptions::Verbosity verbosity,
                        BSONObjBuilder* out) const {
    return {ErrorCodes::IllegalOperation, str::stream() << "Cannot explain cmd: " << getName()};
}
Status Command::explain(OperationContext* opCtx,
                        const string& dbname,
                        const BSONObj& cmdObj,
                        ExplainOptions::Verbosity verbosity,
                        BSONObjBuilder* out) const {
    return {ErrorCodes::IllegalOperation, str::stream() << "Cannot explain cmd: " << getName()};
}