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

You are given an integer n. We say that two integers x and y form a prime number pair if:

1 <= x <= y <= n
x + y == n
x and y are prime numbers

Return the 2D sorted list of prime number pairs [xi, yi]. The list should be sorted in increasing order of xi. If there are no prime number pairs at all, return an empty array.
Note: A prime number is a natural number greater than 1 with only two factors, itself and 1.
 
Please complete the following python code precisely:
```python
class Solution:
    def findPrimePairs(self, n: int) -> List[List[int]]:
```