hash_list = ''.join([
        data['currency'],
        data['vendor_code'],
        data['transaction_date'],
        data['amount'],
        data['success'],
        data['hook_stamp'], # <--- integer
    ])
    hash = hashlib.md5(hash_list).hexdigest()

sequence item 5: expected str instance, int found

 hash_list = ''.join([
        data['currency'],
        data['vendor_code'],
        data['transaction_date'],
        data['amount'],
        data['success'],
        str(data['hook_stamp']).encode('utf-8'),
    ])
    hash = hashlib.md5(hash_list).hexdigest()

sequence item 5: expected str instance, bytes found

Unicode-objects must be encoded before hashing