     /// Added a view as the subview of this SimpleAutoLayout object's superview, and place it above the last subview that we added a constraint through SimpleAutoLayout.
     /// @param item the subview to be added
     /// @param distance the distance between this subview and the last subview
-    /// @param w the subview's width
-    /// @param h the subview's height
-    /// @param aspectRatio the subview's width/height ratio
-    /// @param alignToLast a dictionary where keys are NSLayoutAttribute, the values are the difference between this subview's value on that attribute and the last subview's. (The last subview is the subview which we set layout constraint through SimpleAutoLayout)
-    /// @param endWithMargin if passed in, this subview will have this such distance to the top border of the superview
+    /// @param size the size of the item
+    /// @param alignToLast a dictionary where keys are NSLayoutAttribute, the values are the difference between this subview's value on that attribute and the last subview's. (The last subview is the subview which we set layout constraint through SimpleAutoLayout)
+    /// @param endWithMargin if passed in, this subview will have this such distance to the right border of the superview
+    /// @param safeArea if endWithMargin is used, safeArea = true means the margin should also include safe area margin
     @discardableResult open func goUp(_ item: UIView, distance: CGFloat = 0, size: [SizingParam: CGFloat]? = nil, alignToLast: [NSLayoutConstraint.Attribute: CGFloat]? = nil, endWithMargin: CGFloat? = nil, safeArea: Bool = false) -> SimpleAutoLayout {
         add(item)
         addConstraint(item, a1: .bottom, item2: lastItem, a2: .top, constant: -distance)

    /// Added a view as the subview of this SimpleAutoLayout object's superview, and place it below the last subview that we added a constraint through SimpleAutoLayout.
    /// @param item the subview to be added
    /// @param distance the distance between this subview and the last subview
    /// @param w the subview's width
    /// @param h the subview's height
    /// @param aspectRatio the subview's width/height ratio
    /// @param alignToLast a dictionary where keys are NSLayoutAttribute, the values are the difference between this subview's value on that attribute and the last subview's. (The last subview is the subview which we set layout constraint through SimpleAutoLayout)
    /// @param endWithMargin if passed in, this subview will have this such distance to the bottom border of the superview
    @discardableResult open func goDown(_ item: UIView, distance: CGFloat = 0, size: [SizingParam: CGFloat]? = nil, alignToLast: [NSLayoutConstraint.Attribute: CGFloat]? = nil, endWithMargin: CGFloat? = nil, safeArea: Bool = false) -> SimpleAutoLayout {
        add(item)
        addConstraint(item, a1: .top, item2: lastItem, a2: .bottom, constant: distance)

    /// Added a view as the subview of this SimpleAutoLayout object's superview, and place it to the left of the last subview that we added a constraint through SimpleAutoLayout.
    /// @param item the subview to be added
    /// @param distance the distance between this subview and the last subview
    /// @param size the size of the item
    /// @param alignToLast a dictionary where keys are NSLayoutAttribute, the values are the difference between this subview's value on that attribute and the last subview's. (The last subview is the subview which we set layout constraint through SimpleAutoLayout)
    /// @param endWithMargin if passed in, this subview will have this such distance to the right border of the superview
    /// @param safeArea if endWithMargin is used, safeArea = true means the margin should also include safe area margin
    @discardableResult open func goLeft(_ item: UIView, distance: CGFloat = 0, size: [SizingParam: CGFloat]? = nil, alignToLast: [NSLayoutConstraint.Attribute: CGFloat]? = nil, endWithMargin: CGFloat? = nil, safeArea: Bool = false) -> SimpleAutoLayout {
        add(item)
        addConstraint(item, a1: .right, item2: lastItem, a2: .left, constant:-distance)
