Multiplier in Constraints

[rehannali]

Hi, how can we add multiplier to any constraint
Example snapkit
make.centerY.equalTo(self).multipliedBy(0.8)

Example native:
selectionView.centerXAnchor.constraint(equalTo: safeArea.centerXAnchor, multiplier: 0.8).isActive = true

I don't found a way to add multiplier. It only have constant/padding to constraint.