input: from typing import List
  
  def create_blockchain(blockchain_transactions: List[dict]) -> List[Block]:
      """Create a simple blockchain system in Python. The blockchain consists of a series of blocks, each containing an index, timestamp, data, and the hash of the previous block. The first block, known as the genesis block, is manually added. Each subsequent block is created and added to the chain.
      >>> create_blockchain([{'transaction': 'Alice sends 5 BTC to Bob'}, {'transaction': 'Bob sends 2 BTC to Charlie'}])
      [Block(index=0, timestamp='2023-01-01 12:00:00', data='Genesis Block', previous_hash='0', hash='aaaa'), Block(index=1, timestamp='2023-01-01 12:01:00', data="{'transaction': 'Alice sends 5 BTC to Bob'}", previous_hash='aaaa'), Block(index=2, timestamp='2023-01-01 12:02:00', data="{'transaction': 'Bob sends 2 BTC to Charlie'}", previous_hash='bbbb')]
      """
output:     from hashlib import sha256
      from datetime import datetime
  
      class Block:
          def __init__(self, index, timestamp, data, previous_hash):
              self.index = index
              self.timestamp = timestamp
              self.data = data
              self.previous_hash = previous_hash
              self.hash = self.calculate_hash()
  
          def calculate_hash(self):
              block_string = f"{self.index}{self.timestamp}{self.data}{self.previous_hash}"
              return sha256(block_string.encode()).hexdigest()
  
          def __repr__(self):
              return f"Block(index={self.index}, timestamp='{self.timestamp}', data={self.data}, previous_hash='{self.previous_hash}', hash='{self.hash}')"
  
      blockchain = []
      genesis_block = Block(0, '2023-01-01 12:00:00', 'Genesis Block', '0')
      blockchain.append(genesis_block)
  
      for i, transaction in enumerate(blockchain_transactions, start=1):
          new_block = Block(i, datetime.now().strftime('%Y-%m-%d %H:%M:%S'), str(transaction), blockchain[-1].hash)
          blockchain.append(new_block)
  
      return blockchain