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

Given an array of integers arr of even length n and an integer k.
We want to divide the array into exactly n / 2 pairs such that the sum of each pair is divisible by k.
Return true If you can find a way to do that or false otherwise.
 
Please complete the following python code precisely:
```python
class Solution:
    def canArrange(self, arr: List[int], k: int) -> bool:
```