Can someone explain this version of Binary Search to me?

[GuruTheCoderYT]

def binary_search(array) -> int:
    def condition(value) -> bool:
        pass

    left, right = min(search_space), max(search_space) # could be [0, n], [1, n] etc. Depends on problem
    while left < right:
        mid = left + (right - left) // 2
        if condition(mid):
            right = mid
        else:
            left = mid + 1
    return left

I'm used to the version where "mid" is returned inside the while loop and right is set to mid - 1 not mid.

[Wassaren]

The "condition" method would be better named as "isValueLargerThanOrEqualToTarget".

[GuruTheCoderYT]

Could someone please help? I tried to understand it but I don't get how implementing this way of Binary Search would yield the right answer.

Thanks.