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

You are given an integer array nums. The value of this array is defined as the sum of |nums[i] - nums[i + 1]| for all 0 <= i < nums.length - 1.
You are allowed to select any subarray of the given array and reverse it. You can perform this operation only once.
Find maximum possible value of the final array.
 
Please complete the following python code precisely:
```python
class Solution:
    def maxValueAfterReverse(self, nums: List[int]) -> int:
```