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

Given an integer array nums, return the number of non-empty subarrays with the leftmost element of the subarray not larger than other elements in the subarray.
A subarray is a contiguous part of an array.
 
Please complete the following python code precisely:
```python
class Solution:
    def validSubarrays(self, nums: List[int]) -> int:
```