diff --git a/binary_search_tree/tree.py b/binary_search_tree/tree.py
index cdd5abc..4c24a57 100644
--- a/binary_search_tree/tree.py
+++ b/binary_search_tree/tree.py
@@ -14,35 +14,110 @@ class Tree:
     def __init__(self):
         self.root = None
 
+    def add_helper(self, current_node, key, value ):
+        if current_node == None:
+            return TreeNode(key, value)
+        if key <= current_node.key:
+            current_node.left = self.add_helper(current_node.left, key, value)
+        else:
+            current_node.right = self.add_helper(current_node.right, key, value)
+        return current_node 
+
     # Time Complexity: 
     # Space Complexity: 
     def add(self, key, value = None):
-        pass
+        if self.root == None:
+            self.root = TreeNode(key, value) 
+        else:
+            self.add_helper(self.root, key, value)
 
     # Time Complexity: 
     # Space Complexity: 
     def find(self, key):
-        pass
+        if self.root == None:
+            return None
+        current = self.root
+        while current != None:
+            if current.key == key:
+                return current.value
+            elif  current.key >= key: 
+                current = current.left
+            else:
+                current = current.right
+        return None
 
-    # Time Complexity: 
-    # Space Complexity: 
+    # In-Order: Left, Current, Right
+    def inorder_helper(self, root, inorder_list):
+        if root:
+        # Traverse left
+            self.inorder_helper(root.left, inorder_list)
+        # Traverse root
+            # print(str(root.val) + "->", end='')
+            inorder_list.append({"key" : root.key, "value" : root.value})
+        # Traverse right
+            self.inorder_helper(root.right, inorder_list)
+        return inorder_list
+
+    # # Time Complexity: 
+    # # Space Complexity: 
     def inorder(self):
-        pass
+        inorder_list = []
+        if self.root == None:
+            return inorder_list
+        else:
+            return self.inorder_helper(self.root, inorder_list)
+
+    def preorder_helper(self, root, preorder_list):
+        if root:
+            preorder_list.append({"key" : root.key, "value" : root.value})
+            self.preorder_helper(root.left, preorder_list)
+            self.preorder_helper(root.right, preorder_list)
+        return preorder_list
 
     # Time Complexity: 
     # Space Complexity:     
     def preorder(self):
-        pass
+        preorder_list = []
+        if self.root == None:
+            return preorder_list
+        else:
+            return self.preorder_helper(self.root, preorder_list)
+
+    def postorder_helper(self, root, postorder_list):
+        if root:
+            self.postorder_helper(root.left, postorder_list)
+            self.postorder_helper(root.right, postorder_list)
+            postorder_list.append({"key" : root.key, "value" : root.value})
+        return postorder_list
 
     # Time Complexity: 
     # Space Complexity:     
     def postorder(self):
-        pass
+        postorder_list = []
+        if self.root == None:
+            return postorder_list
+        else:
+            return self.postorder_helper(self.root, postorder_list)
+
+
+    def height_helper(self, root):
+        if root == None:
+            return 0
+        lefth= self.height_helper(root.left)
+        righth = self.height_helper(root.right)
+
+        if lefth > righth:
+            return lefth + 1
+        else:
+            return righth + 1
 
     # Time Complexity: 
     # Space Complexity:     
     def height(self):
-        pass
+        if self.root == None:
+            return 0
+        else:
+            return self.height_helper(self.root)
 
 
 #   # Optional Method
@@ -51,8 +126,6 @@ def height(self):
     def bfs(self):
         pass
 
-        
-
 
 #   # Useful for printing
     def to_s(self):
diff --git a/tests/test_binary_search_tree.py b/tests/test_binary_search_tree.py
index 587d7fb..d74d8dd 100644
--- a/tests/test_binary_search_tree.py
+++ b/tests/test_binary_search_tree.py
@@ -1,7 +1,6 @@
 import pytest
 from binary_search_tree.tree import Tree
 
-
 @pytest.fixture()
 def empty_tree() -> Tree():
     return Tree()
@@ -25,6 +24,7 @@ def test_find_returns_none_for_empty_tree(empty_tree):
 
 def test_can_find_single_root_node(empty_tree):
     empty_tree.add(25, "Kari")
+
     assert empty_tree.find(25) == "Kari"
 
 
@@ -49,7 +49,6 @@ def test_inorder_with_empty_tree(empty_tree):
     answer = empty_tree.inorder()
     assert empty_tree.inorder() == []
 
-
 def test_inorder_with_nodes(tree_with_nodes):
     expected_answer = [
         {
@@ -236,4 +235,4 @@ def test_bfs_with_tree_with_nodes(tree_with_nodes):
     ]
 
     answer = tree_with_nodes.bfs()
-    assert answer == expected_answer
+    assert answer == expected_answer
\ No newline at end of file