@Override
        public String toString() {
            StringBuilder out = new StringBuilder();

            String currentParent = "";
            for (var entry : historyEntries) {
                String parentName = entry.tenant.parentHostname().orElseThrow();
                if (!parentName.equals(currentParent)) {
                    currentParent = parentName;
                    out.append(parentName).append("\n");
                }
                out.append(entry.toString()).append("\n");
            }

            return out.toString();
        }
Provides convenient methods for tallying failures.
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/CapacityChecker.java