'''
Consider a simple data structure called BiNode, which has pointers to two other nodes.

public class BiNode {
    public BiNode node1, node2;
    public int data;
}

The data structure BiNode could be used to represent both a binary tree (where node1 is the left node and node2 is the right node) or a doubly linked list (where node1 is the previous node and node2 is the next node). Implement a method to convert a binary search tree (implemented with BiNode) into a doubly linked list. The values should be kept in order and the operation should be performed in place (that is, on the original data structure).

Hints: 509, 608, 646, 680, 701, 719
'''


def BiNode(s):
    pass

if __name__ == '__main__':
    assert BiNode('') ==
    assert BiNode('') ==
    assert BiNode('') ==
    assert BiNode('') ==
    assert BiNode('') ==
