     
     func top(points:CGFloat) -> UIView {
         if let spv = superview {
-            let c = NSLayoutConstraint(item: self, attribute: .Top, relatedBy: .Equal, toItem: spv, attribute: .Top, multiplier: 1, constant: points)
+            let c = constraint(item: self, attribute: .Top, toItem: spv, constant: points)
             spv.addConstraint(c)
         }
         return self

// MARK: - Position

extension UIView {

    func left(points:CGFloat) -> UIView {
        if let spv = superview {
            let c = NSLayoutConstraint(item: self, attribute: .Left, relatedBy: .Equal, toItem: spv, attribute: .Left, multiplier: 1, constant: points)
            spv.addConstraint(c)
        }
        return self

extension UIView {
    
    func height(points:CGFloat) -> UIView {
        let c = constraint(item: self, attribute: .Height, constant: points)
        addConstraint(c)
        return self
    }
    
    func width(points:CGFloat) -> UIView {
        let c = constraint(item: self, attribute: .Width, constant: points)
        addConstraint(c)
        return self
    }
