input: Write a function to build a simple blockchain system in Python using a `Block` class and a `create_blockchain` function. The `Block` class should include attributes for index, timestamp, data, previous hash, and a function to hash the block contents. The `create_blockchain` function should initialize the blockchain with a genesis block and add subsequent blocks based on a list of transactions. The `print_blockchain` function should print the details of each block in the blockchain.
  
  
  import hashlib
  import json
  
  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.hash_block()
  
   def hash_block(self):
   sha = hashlib.sha256()
   sha.update((str(self.index) + 
   str(self.timestamp) + 
   str(self.data) + 
   str(self.previous_hash)).encode('utf-8'))
   return sha.hexdigest()
  
  def create_blockchain():
   blockchain = [create_genesis_block()]
   previous_block = blockchain[0]
  
   for i in range(1, len(blockchain_transactions)):
   block_to_add = next_block(previous_block, blockchain_transactions[i])
   blockchain.append(block_to_add)
   previous_block = block_to_add
  
  def print_blockchain():
   for block in blockchain:
   block_index = str(block.index)
   block_timestamp = str(block.timestamp)
   block_data = str(block.data)
   block_hash = block.hash
   print(f"Block Index: {block_index}, Timestamp: {block_timestamp}, Data: {block_data}, Hash: {block_hash}")
  
  
  To test the above function, you can create a simple list of transactions and call the `create_blockchain` function followed by the `print_blockchain` function to verify the implementation.
output: 
  def create_blockchain():
   blockchain = [create_genesis_block()]
   previous_block = blockchain[0]
  
   for i in range(1, len(blockchain_transactions)):
   block_to_add = next_block(previous_block, blockchain_transactions[i])
   blockchain.append(block_to_add)
   previous_block = block_to_add
  