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

Given a 0-indexed integer array nums, return the smallest index i of nums such that i mod 10 == nums[i], or -1 if such index does not exist.
x mod y denotes the remainder when x is divided by y.
 
Please complete the following python code precisely:
```python
class Solution:
    def smallestEqual(self, nums: List[int]) -> int:
```