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

A sentence is a string of single-space separated words where each word consists only of lowercase letters.
A word is uncommon if it appears exactly once in one of the sentences, and does not appear in the other sentence.
Given two sentences s1 and s2, return a list of all the uncommon words. You may return the answer in any order.
 
Please complete the following python code precisely:
```python
class Solution:
    def uncommonFromSentences(self, s1: str, s2: str) -> List[str]:
```