class Node:  # This is the Class Node with constructor that contains data variable to type data and left,right pointers.
    def __init__(self, data):
        self.data = data
        self.left = None
        self.right = None


def display(tree):  # In Order traversal of the tree

    if tree is None:
        return

    if tree.left is not None:
        display(tree.left)

    print(tree.data)

    if tree.right is not None:
        display(tree.right)

    return


def depth_of_tree(
    tree,
):  # This is the recursive function to find the depth of binary tree.
    if tree is None:
        return 0
    else:
        depth_l_tree = depth_of_tree(tree.left)
        depth_r_tree = depth_of_tree(tree.right)
        if depth_l_tree > depth_r_tree:
            return 1 + depth_l_tree
        else:
            return 1 + depth_r_tree


def is_full_binary_tree(
    tree,
):  # This functions returns that is it full binary tree or not?
    if tree is None:
        return True
    if (tree.left is None) and (tree.right is None):
        return True
    if (tree.left is not None) and (tree.right is not None):
        return is_full_binary_tree(tree.left) and is_full_binary_tree(tree.right)
    else:
        return False


def main():  # Main func for testing.
    tree = Node(1)
    tree.left = Node(2)
    tree.right = Node(3)
    tree.left.left = Node(4)
    tree.left.right = Node(5)
    tree.left.right.left = Node(6)
    tree.right.left = Node(7)
    tree.right.left.left = Node(8)
    tree.right.left.left.right = Node(9)

    print(is_full_binary_tree(tree))
    print(depth_of_tree(tree))
    print("Tree is: ")
    display(tree)


if __name__ == "__main__":
    main()

class Node:  # This is the Class Node with a constructor that contains data variable to type data and left, right pointers.
    def __init__(self, data):
        self.data = data
        self.left = None
        self.right = None


def display(tree):  # In Order traversal of the tree

    if tree is None:
        return

    if tree.left is not None:
        display(tree.left)

    print(tree.data)

    if tree.right is not None:
        display(tree.right)

    return


def depth_of_tree(
    tree,
):  # This is the recursive function to find the depth of binary tree.
    if tree is None:
        return 0
    else:
        depth_l_tree = depth_of_tree(tree.left)
        depth_r_tree = depth_of_tree(tree.right)
        if depth_l_tree > depth_r_tree:
            return 1 + depth_l_tree
        else:
            return 1 + depth_r_tree


def is_full_binary_tree(
    tree,
):  # This function returns that is it full binary tree or not?
    if tree is None:
        return True
    if (tree.left is None) and (tree.right is None):
        return True
    if (tree.left is not None) and (tree.right is not None):
        return is_full_binary_tree(tree.left) and is_full_binary_tree(tree.right)
    else:
        return False


def main():  # Main function for testing.
    tree = Node(1)
    tree.left = Node(2)
    tree.right = Node(3)
    tree.left.left = Node(4)
    tree.left.right = Node(5)
    tree.left.right.left = Node(6)
    tree.right.left = Node(7)
    tree.right.left.left = Node(8)
    tree.right.left.left.right = Node(9)

    print(is_full_binary_tree(tree))
    print(depth_of_tree(tree))
    print("Tree is: ")
    display(tree)


if __name__ == "__main__":
    main()

Update basic_binary_tree.py (#1833)