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

Given a string num which represents an integer, return true if num is a strobogrammatic number.
A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down).
 
Please complete the following python code precisely:
```python
class Solution:
    def isStrobogrammatic(self, num: str) -> bool:
```