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

An array is monotonic if it is either monotone increasing or monotone decreasing.
An array nums is monotone increasing if for all i <= j, nums[i] <= nums[j]. An array nums is monotone decreasing if for all i <= j, nums[i] >= nums[j].
Given an integer array nums, return true if the given array is monotonic, or false otherwise.
 
Please complete the following python code precisely:
```python
class Solution:
    def isMonotonic(self, nums: List[int]) -> bool:
```