code: private void calculateCalendarHashChainOutput() throws KSIException {
          ChainResult lastRes = null;
          for (AggregationHashChain chain : aggregationChains) {
              if (lastRes == null) {
                  lastRes = chain.calculateOutputHash(0L);
              } else {
                  lastRes = chain.calculateOutputHash(lastRes.getLevel());
              }
              LOGGER.debug("Output hash of chain: {} is {}", chain, lastRes.getOutputHash());
          }
      }
docs: This method is used to verify signature consistency.