How will access NSSplitViewDelegate methods, constrains etc.

I am using NSSplitView in my application. I was trying to access NSSplitViewDelegate methods, constrains etc. I tried a lot but not able to accesses NSSplitViewDelegate methods, constrains etc. I am uploading my demo app. Kindly correct me where I am going wrong to access the following function.

splitView(NSSplitView, constrainMaxCoordinate: CGFloat, ofSubviewAt: Int)

splitView(NSSplitView, constrainMinCoordinate: CGFloat, ofSubviewAt: Int)

and In attached 10.png left left spliter divider thick(seems two line), what should me do to display it as single (right spliter divider)