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

You are given a binary string s, and two integers num1 and num2. num1 and num2 are coprime numbers.
A ratio substring is a substring of s where the ratio between the number of 0's and the number of 1's in the substring is exactly num1 : num2.

For example, if num1 = 2 and num2 = 3, then "01011" and "1110000111" are ratio substrings, while "11000" is not.

Return the number of non-empty ratio substrings of s.
Note that:

A substring is a contiguous sequence of characters within a string.
Two values x and y are coprime if gcd(x, y) == 1 where gcd(x, y) is the greatest common divisor of x and y.

 
Please complete the following python code precisely:
```python
class Solution:
    def fixedRatio(self, s: str, num1: int, num2: int) -> int:
```