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

Given three integer arrays arr1, arr2 and arr3 sorted in strictly increasing order, return a sorted array of only the integers that appeared in all three arrays.
 
Please complete the following python code precisely:
```python
class Solution:
    def arraysIntersection(self, arr1: List[int], arr2: List[int], arr3: List[int]) -> List[int]:
```