class Cipher(object):
    def __init__(self):
        pass


class Caesar(object):
    def __init__(self):
        pass

@@ -28,32 +28,126 @@
 ef __init__(self
+, key=None):%0A        pass%0A%0A    def encode(self, text):%0A        pass%0A%0A    def decode(self, text
 ):%0A        pass%0A

Add parameters to exercise placeholder to resolve #640