Please solve the programming task below using a self-contained code snippet in a markdown code block.

The set [1, 2, 3, ..., n] contains a total of n! unique permutations.
By listing and labeling all of the permutations in order, we get the following sequence for n = 3:

"123"
"132"
"213"
"231"
"312"
"321"

Given n and k, return the kth permutation sequence.
 
Please complete the following python code precisely:
```python
class Solution:
    def getPermutation(self, n: int, k: int) -> str:
```