Permutations

def permutations():
    sequence = [0,1,2,3,4,5,6]
    sequenceCopy2 = [0, 1, 2, 3, 4, 5, 6]
    sequenceCopy = [2,6,0,5,1,3,4]
    while len(sequence) > 1:
        chain = get_chain(sequence, sequenceCopy)
        sequence = diff(sequence, chain)
        print(chain)


def diff(list1, list2):
    c = set(list1).union(set(list2)) # or c = set(list1) | set(list2)
    d = set(list1).intersection(set(list2)) # or d = set(list1) & set(list2)
    return list(c - d)


def get_chain(sequence, permutation):
    chain = []
    index1 = permutation.index(sequence[0])
    chain.append(sequence[0])
    chain.append(index1)
    src = index1
    while True:
        chain.append(permutation.index(src))
        if chain[0] == chain[len(chain)-1]:
            return chain
        src = permutation.index(src)

permutations()