1. Assume that general trees are implemented using a Treenode class that includes the following fields and methods: /I fields private T data; private List> getchildren) return children) For efficiency, use an iterator to access the children in the list returned by the method getchildren (as we've done in lecture). You may assume that getChildren never returns null: if a node is a leaf, then getChildren will return a non-null list containing zero elements. Write an isBinary method whose header is given below. public boolean 1sB1nary( TreenodecT> n The method should determine if the general tree rooted by n is also a binary tree. A binary tree is recursively defined as o An empty tree is binary. o A leaf node is a binary tree. o A node with 1 or 2 children is binary if each child is itself a binary tree