 public func - (left: PartialFlexibleConstraint, right: UIView) -> [UIView] {
     if let views = left.views {
         if let spv = right.superview {
-            let c = constraint(item: right, attribute: .left,
+            let c = constraint(item: right, attribute: .leading,
                                relatedBy: left.fm.relation, toItem: views.last,
-                               attribute: .right,
+                               attribute: .trailing,
                                constant: left.fm.points)
             spv.addConstraint(c)
         }
         return views + [right]
     } else {
         if let spv = right.superview {
-            let c = constraint(item: right, attribute: .left,
+            let c = constraint(item: right, attribute: .leading,
                                relatedBy: left.fm.relation, toItem: left.view1!,
-                               attribute: .right,
+                               attribute: .trailing,
                                constant: left.fm.points)
             spv.addConstraint(c)
         }

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

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