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

The k-beauty of an integer num is defined as the number of substrings of num when it is read as a string that meet the following conditions:

It has a length of k.
It is a divisor of num.

Given integers num and k, return the k-beauty of num.
Note:

Leading zeros are allowed.
0 is not a divisor of any value.

A substring is a contiguous sequence of characters in a string.
 
Please complete the following python code precisely:
```python
class Solution:
    def divisorSubstrings(self, num: int, k: int) -> int:
```