code: def get_atlas_zonefile_info_at( self, block_id ):
          
          nameops = self.get_all_blockstack_ops_at( block_id )
          ret = []
          for nameop in nameops:
              if nameop.has_key('op') and op_get_opcode_name(nameop['op']) in ['NAME_UPDATE', 'NAME_IMPORT', 'NAME_REGISTRATION', 'NAME_RENEWAL']:
  
                  assert nameop.has_key('value_hash')
                  assert nameop.has_key('name')
                  assert nameop.has_key('txid')
  
                  if nameop['value_hash'] is not None:
                      ret.append( {'name': nameop['name'], 'value_hash': nameop['value_hash'], 'txid': nameop['txid']} )
  
          return ret
docs: Get the blockchain-ordered sequence of names, value hashes, and txids.
          added at the given block height.  The order will be
          in tx-order.
  
          Return [{'name': name, 'value_hash': value_hash, 'txid': txid}]