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

You are given a 0-indexed string num of length n consisting of digits.
Return true if for every index i in the range 0 <= i < n, the digit i occurs num[i] times in num, otherwise return false.
 
Please complete the following python code precisely:
```python
class Solution:
    def digitCount(self, num: str) -> bool:
```