def filled_tree():
    A = Node(6)
    a = BST()
    a.root = A
    A.left = 4
    A.right = 7
    A.left.left = 3
    A.left.right = 5
    A.right.right = 8
    a._size = 6
    return a
def uneven_tree():
    A = Node(6)
    a = BST()
    a.root = A
    A.left = 4
    A.right = 7
    A.left.left = 3
    A.left.right = 5
    A.right.right = 8
    A.right.right.right = 9
    A.right.right.right.right = 10
    a._size = 6
    return a