input: Write a function to build a simple blockchain system in Python.
  
  ### Function Implementation:
  
  
  import hashlib
  import time
  
  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_genesis_block():
      return Block(0, time.time(), "Genesis Block", "0")
  
  def next_block(last_block, data):
      this_index = last_block.index + 1
      this_timestamp = time.time()
      this_data = data
      this_hash = last_block.hash
      return Block(this_index, this_timestamp, this_data, this_hash)
  
  def create_blockchain(transactions):
      blockchain = [create_genesis_block()]
      previous_block = blockchain[0]
  
      for data in transactions:
          block_to_add = next_block(previous_block, data)
          blockchain.append(block_to_add)
          previous_block = block_to_add
  
      return blockchain
  
  def print_blockchain(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}")
  
  # Test cases
  transactions1 = ["data1", "data2", "data3"]
  blockchain1 = create_blockchain(transactions1)
  print_blockchain(blockchain1)
  
  transactions2 = []
  blockchain2 = create_blockchain(transactions2)
  print_blockchain(blockchain2)
  
output: def create_blockchain(transactions):
      blockchain = [create_genesis_block()]
      previous_block = blockchain[0]
  
      for data in transactions:
          block_to_add = next_block(previous_block, data)
          blockchain.append(block_to_add)
          previous_block = block_to_add
  
      return blockchain