code: def index_blockchain(self, block_start, block_end):
          
          log.debug("Processing subdomain updates for zonefiles in blocks {}-{}".format(block_start, block_end))
          
          res = self.find_zonefile_subdomains(block_start, block_end)
          zonefile_subdomain_info = res['zonefile_info']
  
          self.process_subdomains(zonefile_subdomain_info)
docs: Go through the sequence of zone files discovered in a block range, and reindex the names' subdomains.