def calculate_hash(self):
    return sha256((((str(self.from_address) + str(self.to_address)) + str(self.amount)) + self.id).encode()).hexdigest()
def calculate_hash(self):
    return sha256((((str(self.from_address) + str(self.to_address)) + str(self.amount)) + self.id).encode()).hexdigest()