def nextPermutation(self, nums):
    permute_generator = self.permuteHelper(nums, 0, len(nums) - 1)
    for item in permute_generator:
        print(item)

def permuteHelper(self, a, l, r):
    if l == r:
        yield a
    else:
        for i in range(l, r + 1):
            a[l], a[r] = a[r], a[l]
            self.permuteHelper(a, l + 1, r)
            a[l], a[i] = a[i], a[l]