获得一组数的全排列

def (xs):
 
    if isinstance(xs,str):
        def str2charArray(str):
            charArray = []
            for i in str:
                charArray.append(i)
            return charArray
        xs = str2charArray(xs)

    if len(xs) == 0 or len(xs) == 1:
        return [xs]

    result = []

    for i in range(0,len(xs)):
        temp_list = xs[:]
        temp_list.pop(i)
        temp = permutation(temp_list)
        for j in temp:
            j.insert(0,xs[i])
            result.append(j)

    return result