Ex$2.$

Nodes

Depth

points$)$

Using an iterative function Depth$($self$),$ calculate the depth of each node in the current tree. Each node's depth must be saved in the node itself $($using instance field$\_$depth$).$ The printIn$0$ must be changed such that it prints the node's values and their depth like this: $2(2),3(3),7(1),9(2),12(0),14(2),30(1),39(2).$