public Boolean isUnderMinIsr() {
            return !hasLeader() ||  info.isr().size() < minIsrCount();
        }
ensures topic existence and throws exception if topic doesn't exist

@param foundTopicIds        Topics that were found to match the requested topic id.
@param requestedTopicId     Id of the topic that was requested.
@param requireTopicIdExists Indicates if the topic needs to exist for the operation to be successful.
                            If set to true, the command will throw an exception if the topic with the
                            requested id does not exist.
tools/src/main/java/org/apache/kafka/tools/TopicCommand.java