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

Given an integer array nums, you need to find one continuous subarray such that if you only sort this subarray in non-decreasing order, then the whole array will be sorted in non-decreasing order.
Return the shortest such subarray and output its length.
 
Please complete the following python code precisely:
```python
class Solution:
    def findUnsortedSubarray(self, nums: List[int]) -> int:
```