'Give a list of Links that each contain node n, flips any links so
that n is always the first element of the link.'

@staticmethod
def order(links, n):

    r = []
    for l in links:
        assert (n in l)
        if (l._n[0] == n):
            r.append(l)
        else:
            r.append(l.flip())
    return r
