         }
     }
     
-    public func container() -> Self {
+    @discardableResult public func container() -> Self {
         
-        var frame = CGRect()
+        var frame = CGRect.zero
         for subview in self.view.subviews {
             frame = frame.union(subview.frame)
         }

        return self
    }

    public func sizeToFit() -> Self {
        
        view.sizeToFit()
        setHighPriorityValue(view.bounds.width, forRelation: .Width)

        return self
    }
    
    @discardableResult public func sizeThatFits(size: CGSize) -> Self {
        
        let fitSize = view.sizeThatFits(size)
        let width = min(size.width, fitSize.width)
