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

Given an integer array arr, return the mean of the remaining integers after removing the smallest 5% and the largest 5% of the elements.
Answers within 10-5 of the actual answer will be considered accepted.
 
Please complete the following python code precisely:
```python
class Solution:
    def trimMean(self, arr: List[int]) -> float:
```