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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def index_blockchain(self, block_start, block_end):
 """ Go through the sequence of zone files discovered in a block range, and reindex the names' subdomains. """

        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)