stack = []


class TreeNode():
    def __init__(self, item, left = None, right = None):
        self.item = item
        self.left = left
        self.right = right

def inOrder(head):

    if head == None:
        return

    print(f"[Moving to left node: {head.left.item}]" if not head.left is None else "[Moving to node: None]")
    stack.append(head.item)
    print(f"[Pushing current node to Stack: {stack} ]\n")
    inOrder(head.left)

    stack.pop()
    print(f"[Popping current node from Stack: {stack} ]")
    print(f"[Returned to previous node: {head.item}]\n")

    print(f"PRINT: {head.item}\n")

    print(f"[Moving to right node: {head.right.item}]" if not head.right is None else "[Moving to node: None]")
    stack.append(head.item)
    print(f"[Pushing current node to Stack: {stack} ]\n")
    inOrder(head.right)


h = TreeNode(4, TreeNode(2, TreeNode(1), TreeNode(3)), TreeNode(6, TreeNode(5), TreeNode(7)))

# h =
#         4
#         
#      /     \
#     2       6
#    /\       /\
#   1  3     5  7

inOrder(h)