 @discardableResult
 public func - (left: [UIView], right: SteviaRightFlexibleMargin) -> [UIView] {
     if let spv = left.last!.superview {
-        let c = constraint(item: spv, attribute: .right,
+        let c = constraint(item: spv, attribute: .trailing,
                            relatedBy: right.fm.relation,
                            toItem: left.last!,
-                           attribute: .right,
+                           attribute: .trailing,
                            constant: right.fm.points)
         spv.addConstraint(c)
     }

@discardableResult
public func - (left: UIView, right: SteviaRightFlexibleMargin) -> UIView {
    if let spv = left.superview {
        let c = constraint(item: spv, attribute: .right,
                           relatedBy: right.fm.relation, toItem: left,
                           attribute: .right,
                           constant: right.fm.points)
        spv.addConstraint(c)
    }

@discardableResult
public func - (left: SteviaLeftFlexibleMargin, right: UIView) -> UIView {
    if let spv = right.superview {
        let c = constraint(item: right, attribute: .leading,
                           relatedBy: left.fm.relation, toItem: spv,
                           attribute: .leading,
                           constant: left.fm.points)
        spv.addConstraint(c)
    }
