input: from typing import Dict
  
  
  def add_block_to_blockchain(data: Dict[str, str], blockchain: Blockchain) -> str:
      """ Adds a block to the provided blockchain using the given data.
      The data dictionary must include 'timestamp' and 'data' keys.
      Returns the updated blockchain in JSON format.
      >>> blockchain = Blockchain()
      >>> add_block_to_blockchain({'timestamp': '2023-10-01', 'data': 'Transaction1'}, blockchain)
      '[{"index": 0, "timestamp": "2023-10-01", "data": "Transaction1", "previous_hash": null, "hash": "..."}]'
      """
output:     block = {
          'index': len(blockchain.chain),
          'timestamp': data['timestamp'],
          'data': data['data'],
          'previous_hash': blockchain.get_latest_block().hash if blockchain.chain else None,
          'hash': ''
      }
      block['hash'] = blockchain.calculate_hash(block)
      blockchain.chain.append(block)
      return blockchain.to_json()