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

Given a string s, reverse only all the vowels in the string and return it.
The vowels are 'a', 'e', 'i', 'o', and 'u', and they can appear in both lower and upper cases, more than once.
 
Please complete the following python code precisely:
```python
class Solution:
    def reverseVowels(self, s: str) -> str:
```