blockchain.py

import hashlib

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.calc_hash()

    def calc_hash(self):
        sha = hashlib.sha256()
        sha.update(str(self.index) + str(self.timestamp) + str(self.data) + str(self.previous_hash))
        return sha.hexdigest()


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

    def create_genesis_block(self):
        return Block(0, "01/01/2020", "Genesis block", "0")

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

    def add_block(self, new_block):
        new_block.previous_hash = self.get_latest_block().hash
        new_block.hash = new_block.calc_hash()
        self.chain.append(new_block)

bc = Blockchain()
bc.add_block(Block(1, "01/02/2020", { "amount": 4 }))
bc.add_block(Block(2, "01/03/2020", { "amount": 8 }))

print(bc.chain)