Searching elements in tree

Binary_tree.py

def bst_insert(root, node):
    last_node = None
    current_node = root

    while current_node is not None:
        last_node = current_node
        if node.data < current_node.data:
            current_node = current_node.left
        else:
            current_node = current_node.right

    if last_node is None:
        # tree was empty, node is the only node, hence root
        root = node
    elif node.data < last_node.data:
        last_node.add_right(node)
    else:
        last_node.add_right(node)

    return root                        

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

    def __repr__(self):
        return repr(self.data)

    def add_left(self, node):
        self.left = node
        if node is not None:
            node.parent = self

    def add_right(self, node):
        self.right = node
        if node is not None:
            node.parent = self


def bst_insert(root, node):
    # আগের কোডের মতো হবে
    """
              _10_
             /    \
            5     17
           / \   /  \
          3   7 12  19
         / \ 
        1   4 

    """    
def create_bst():
    ten = TreeNode(10)
    five = TreeNode(5)
    seventeen = TreeNode(17)
    ten.add_left(five)
    ten.add_right(seventeen)
    three = TreeNode(3)
    seven = TreeNode(7)
    five.add_left(three)
    five.add_right(seven)
    one = TreeNode(1)
    four = TreeNode(4)
    three.add_left(one)
    three.add_right(four)
    twelve = TreeNode(12)
    nineteen = TreeNode(19)
    seventeen.add_left(twelve)
    seventeen.add_right(nineteen)
    # now return to the root node
    return ten

if __name__ == "__main__":
    root = create_bst()
    print(root)
# searching function for binary tree
def bst_search(node, key):
    while node is not None:
        if node.data == key:
            return node
        if key < node.data:
            node = node.left
        else:
            node = node.right

    return node

if __name__ == "__main__":
    root = create_bst()

    for key in [7, 8]:
        print("searching", key)
        result = bst_search(root, key)
        print(result)