class CryptoAssets():
    def __init__(self):
        self.blockchain = [
            self.make_genesis_block()
        ]
        self.next_block_index = 1
        self.public_ledger = {
            'Alice': {'Tesla Model 3': 1, '200 shares of TSLA': 1},
            'James': {'9425 Sunset Blvd, Beverly Hills, CA 90210': 1}
        }
        self.transactions = []