input: 
  def build_simple_blockchain() -> None:
      """ Build a simple blockchain system in Python and print it out.
      >>> build_simple_blockchain()
      Blockchain:
      Index: 0, Timestamp: some_timestamp, Data: Genesis Block, Hash: some_hash
      Index: 1, Timestamp: some_timestamp, Data: Transaction Data 1, Hash: some_hash
      Index: 2, Timestamp: some_timestamp, Data: Transaction Data 2, Hash: some_hash
      """
  
output:     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 hashlib.sha256(block_string.encode()).hexdigest()
  
      class Blockchain:
          def __init__(self):
              self.chain = [self.create_genesis_block()]
  
          def create_genesis_block(self):
              return Block(0, "01/01/2023", "Genesis Block", "0")
  
          def add_block(self, data):
              previous_block = self.chain[-1]
              new_index = previous_block.index + 1
              new_timestamp = datetime.datetime.now().strftime("%d/%m/%Y %H:%M:%S")
              new_block = Block(new_index, new_timestamp, data, previous_block.hash)
              self.chain.append(new_block)
  
      blockchain = Blockchain()
      blockchain.add_block("Transaction Data 1")
      blockchain.add_block("Transaction Data 2")
  
      print("Blockchain:")
      for block in blockchain.chain:
          print(f"Index: {block.index}, Timestamp: {block.timestamp}, Data: {block.data}, Hash: {block.hash}")