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

Given an integer array nums, return the value of the bitwise OR of the sum of all possible subsequences in the array.
A subsequence is a sequence that can be derived from another sequence by removing zero or more elements without changing the order of the remaining elements.
 
Please complete the following python code precisely:
```python
class Solution:
    def subsequenceSumOr(self, nums: List[int]) -> int:
```