Pay with Pi

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.calculate_hash()

    def calculate_hash(self):
        block_string = str(self.index) + str(self.timestamp) + str(self.data) + str(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):
        genesis_block = Block(0, time.time(), "Genesis Block", "0")
        self.chain.append(genesis_block)

    def add_block(self, data):
        previous_block = self.chain[-1]
        new_block = Block(len(self.chain), time.time(), data, previous_block.hash)
        self.chain.append(new_block)

    def is_chain_valid(self):
        for i in range(1, len(self.chain)):
            current_block = self.chain[i]
            previous_block = self.chain[i-1]
            if current_block.hash != current_block.calculate_hash():
                return False
            if current_block.previous_hash != previous_block.hash:
                return False
        return True

# Create a Blockchain
blockchain = Blockchain()

# Add some blocks to the chain
blockchain.add_block("Block 1 Data")
blockchain.add_block("Block 2 Data")
blockchain.add_block("Block 3 Data")

# Print the blockchain
for block in blockchain.chain:
    print("Block {}:".format(block.index))
    print("Timestamp: {}".format(str(block.timestamp)))
    print("Data: {}".format(block.data))
    print("Previous Hash: {}".format(block.previous_hash))
    print("Hash: {}".format(block.hash))
    print()