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

Given an array of digit strings nums and a digit string target, return the number of pairs of indices (i, j) (where i != j) such that the concatenation of nums[i] + nums[j] equals target.
 
Please complete the following python code precisely:
```python
class Solution:
    def numOfPairs(self, nums: List[str], target: str) -> int:
```