Expression engine: Get entity SegmentId

Who would benefit?

User of Expression Enginge

What impact would it make?

Enable expressions based on segment

How should it work?

Expression to get Segment
=SEGMENTID()
=FIRSTLINKEDENTITYSEGMENTID()

Why is it needed?

I want to have the ability to get the segment of an entity.
I also want to have the ability to get the parent entity segmentid, so that I can update my current enity according to that segment.