Amigos recursivos

#!/usr/bin/env python
# -*- coding: utf-8 -*-

class Member:

    def __init__(self, name, email):                    # Constructor
        self.name = name
        self.email = email
        self.friends = []

    def addFriend(self, m):
        self.friends.append(m)

    def listFriends(self, l=0, s=[]):                   # l => Nivel. s => Lista acumuladora.
        if(len(s) <= l):
            s.append(self.name)
        else:
            s[l] += "\t"+self.name

        for f in self.friends:
            f.listFriends(l+1, s)

        if(l==0):
            return self.toTable(s)

    def toTable(self, s):                               # Maquilla la lista de amigos en formato tabla

        res = ["--- "+s[0]+" ---\n"]
        del s[0]

        i = 0
        for c in s:
            i += 1
            res.append('Nivel '+str(i)+':\t'+c)

        return "\n".join(res)

def main():

    # Crear miembros

    a = Member('a', '[email protected]')      # Raiz          Nivel 0

    b = Member('b', '[email protected]')      # Amigos de a   Nivel 1
    c = Member('c', '[email protected]')
    d = Member('d', '[email protected]')

    e = Member('e', '[email protected]')      # Amigos de b   Nivel 2
    f = Member('f', '[email protected]')

    g = Member('g', '[email protected]')      # Amigos de c   Nivel 2
    h = Member('h', '[email protected]')

    i = Member('i', '[email protected]')      # Amigos de d   Nivel 2

    j = Member('j', '[email protected]')      # Amigos de e   Nivel 3
    k = Member('k', '[email protected]')
    l = Member('l', '[email protected]')

    m = Member('m', '[email protected]')      # Amigos de i   Nivel 3
    n = Member('n', '[email protected]')

    o = Member('o', '[email protected]')      # Amigos de k   Nivel 4

    p = Member('p', '[email protected]')      # Amigos de o   Nivel 5
    q = Member('q', '[email protected]')

    # Anidar Miembros

    a.addFriend(b)                  # Nivel 1
    a.addFriend(c)
    a.addFriend(d)

    b.addFriend(e)                  # Nivel 2
    b.addFriend(f)

    c.addFriend(g)
    c.addFriend(h)

    d.addFriend(i)

    e.addFriend(j)                  # Nivel 3
    e.addFriend(k)
    e.addFriend(l)

    i.addFriend(m)
    i.addFriend(n)

    k.addFriend(o)                  # Nivel 4

    o.addFriend(p)                  # Nivel 5
    o.addFriend(q)

    print a.listFriends()

    return 0

if __name__ == '__main__':
    main()