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

Given an integer array nums of length n, you want to create an array ans of length 2n where ans[i] == nums[i] and ans[i + n] == nums[i] for 0 <= i < n (0-indexed).
Specifically, ans is the concatenation of two nums arrays.
Return the array ans.
 
Please complete the following python code precisely:
```python
class Solution:
    def getConcatenation(self, nums: List[int]) -> List[int]:
```