text: from . import BlockchainEvent
  
  
  class BlockchainList:
      '''
  
      '''
      '''
      A class to hold records of blockchain events
      '''
      def __init__(self, headings):
          '''
  
          :param headings: list
          :param blockchain_items_iter: list[BlockchainItem]
          '''
          self._headings = headings
          self._blockchain_items = {
  
          }
  
      def append(self, blockchain_item, url):
          '''
          Adds a blockchain item to the list
          :param blockchain_item: BlockchainItem
          :return: bool
          '''
          if type(blockchain_item) is BlockchainEvent:
              if url in self._blockchain_items:
                  self._blockchain_items[url].append(blockchain_item)
              else:
                  self._blockchain_items[url] = [blockchain_item]
              return True
          return False
  
      def write_spreadsheet(self):
          pass
  
      @property
      def headings(self):
          return self._headings
  
      @property
      def blockchain_items(self):
          return self._blockchain_items
  
      def __repr__(self):
          return 'Data Lakes: {}, Headings: {}'.format(len(self.blockchain_items), self.headings)
  