# Learn Tree Traversal by Building a Binary Search Tree - Step 51

### Tell us what’s happening:

im stuck it says your check condition should be if node but my condtion is if node

``````
class TreeNode:

def __init__(self, key):
self.key = key
self.left = None
self.right = None

def __str__(self):
return str(self.key)

class BinarySearchTree:

def __init__(self):
self.root = None

def _insert(self, node, key):
if node is None:
return TreeNode(key)

if key < node.key:
node.left = self._insert(node.left, key)
elif key > node.key:

node.right = self._insert(node.right, key)
return node

def insert(self, key):
self.root = self._insert(self.root, key)

def _search(self, node, key):
if node is None or node.key == key:
return node
if key < node.key:
return self._search(node.left, key)
return self._search(node.right, key)

def search(self, key):
return self._search(self.root, key)

def _delete(self, node, key):
if node is None:
return node
if key < node.key:
node.left = self._delete(node.left, key)
elif key > node.key:
node.right = self._delete(node.right, key)
else:
if node.left is None:
return node.right
elif node.right is None:
return node.left

node.key = self._min_value(node.right)
node.right = self._delete(node.right, node.key)

return node

def delete(self, key):
self.root = self._delete(self.root, key)

def _min_value(self, node):
while node.left is not None:
node = node.left
return node.key

# User Editable Region

def _inorder_traversal(self, node, result):
if node is not None:
self._inorder_traversal(node.left, result)

# User Editable Region

bst = BinarySearchTree()

nodes = [50, 30, 20, 40, 70, 60, 80]

for node in nodes:
bst.insert(node)

# print('Search for 80:', bst.search(80))

``````

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### Challenge Information:

Learn Tree Traversal by Building a Binary Search Tree - Step 51

When you’re using ‘if’ statements, a way to check if a string, list, dictionary, etc. is empty or not is to use:

``````if x:
``````

which returns true and executes the the code inside the if statement if there is something in x, otherwise it returns false and does not execute - if that makes sense.

So try doing that with ‘node’, and since you want it to execute if ‘node’ is NOT empty, you only need ‘if node:’

Apart from that everything else looks perfect!

wow, that was perfectly explained lol i ask chatgpt alot of the times to explain and it doesnt do it as well

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