Untitled

import hashlib
import json

class Block:
    def __init__(self, timestamp, previous_hash, transactions):
        self.timestamp = timestamp
        self.previous_hash = previous_hash
        self.transactions = transactions
        self.hash = hashlib.sha256(json.dumps(self.__dict__).encode('utf-8')).hexdigest()

class Transaction:
    def __init__(self, sender, recipient, amount):
        self.sender = sender
        self.recipient = recipient
        self.amount = amount

class Blockchain:
    def __init__(self):
        self.chain = []
        self.create_genesis_block()

    def create_genesis_block(self):
        genesis_block = Block(timestamp='2023-11-15', previous_hash='0', transactions=[])
        self.chain.append(genesis_block)

    def add_block(self, block):
        if block.previous_hash != self.chain[-1].hash:
            raise ValueError('Invalid previous hash')
        self.chain.append(block)

    def get_latest_block(self):
        return self.chain[-1]

    def is_valid_block(self, block):
        if block.hash != hashlib.sha256(json.dumps(block.__dict__).encode('utf-8')).hexdigest():
            return False
        if block.previous_hash != self.get_latest_block().hash:
            return False
        return True

blockchain = Blockchain()

# Create transactions
transaction1 = Transaction(sender='Alice', recipient='Bob', amount=10)
transaction2 = Transaction(sender='Bob', recipient='Charlie', amount=5)

# Create a block
new_block = Block(timestamp='2023-11-16', previous_hash=blockchain.get_latest_block().hash, transactions=[transaction1, transaction2])

# Add the block to the blockchain
blockchain.add_block(new_block)

print(json.dumps(blockchain.chain, indent=4))