input: Write a python function to create a blockchain and print its contents.
  assert isinstance(create_blockchain(), list), "Blockchain should be a list"
  assert len(create_blockchain()) > 0, "Blockchain should not be empty"
  assert isinstance(create_blockchain()[0], Block), "First element of blockchain should be a Block instance"
output: class Block:
      def __init__(self, index, previous_hash, timestamp, data, hash):
          self.index = index
          self.previous_hash = previous_hash
          self.timestamp = timestamp
          self.data = data
          self.hash = hash
  
  def create_genesis_block():
      return Block(0, "0", 0, "Genesis Block", "0")
  
  def create_blockchain():
      blockchain = [create_genesis_block()]
      return blockchain