class Node(object):
    pass

def menu(prompt, decisions):
    print("> %s" % prompt)
    for i,decision in enumerate(decisions):
        print("%d. %s" % (i,decision))
    answer = int(input("Answer: "))
    return answer

class DecisionNode(Node):
    def __init__(self, question):
        self.question = question
        self.decisions = []

    def addDecision(self, response, node):
        self.decisions.append( (response,node) )

    def display(self):
        i = menu(self.question, [ d[0] for d in self.decisions ])
        return self.decisions[i][1]

class AnswerNode(Node):
    def __init__(self, answer):
        self.answer = answer

    def display(self):
        print(self.answer)
        return None


if __name__ == "__main__":
    high = AnswerNode("hohes Risiko")
    medium = AnswerNode("mittleres Risiko")
    low = AnswerNode("niedriges Risiko")

    n6 = DecisionNode("Einkommen?")
    n6.addDecision("0 Eur bis 15 Tsd Eur", high)
    n6.addDecision("15 Tsd Eur bis 35 Tsd Eur", medium)
    n6.addDecision("ueber 35 Tsd Eur", low)

    n4 = DecisionNode("Sicherheiten?")
    n4.addDecision("keine", n6)
    n4.addDecision("angemessen", low)

    n3 = DecisionNode("Verschuldung?")
    n3.addDecision("hoch", n4)
    n3.addDecision("niedrig", low)

    n2 = DecisionNode("Sicherheiten?")
    n2.addDecision("keine", high)
    n2.addDecision("angemessen", medium)

    n1 = DecisionNode("Verschuldung?")
    n1.addDecision("hoch", high)
    n1.addDecision("niedrig", n4)

    n0 = DecisionNode("Kreditwuerdigkeit?")
    n0.addDecision("unbekannt",n1)
    n0.addDecision("schlecht",n2)
    n0.addDecision("gut",n3)

    node = n0

    while node is not None:
        node = node.display()