Miguel Quiroz

# Pre-order traversal binary tree
def preorder_traversal(node):
  if not node: 
    return None

  print(node.val)
  preorder_traversal(node.left)
  preorder_traversal(node.right)

# In-order traversal binary tree

  def inorder_traversal(node):
    if not node: 
      return None

    inorder_traversal(node.left)
    print(node.val)
    inorder_traversal(node.right)

# Post-order traversal binary tree
  def postorder_traversal(node):
    if not node: 
      return None
    
    postorder_traversal(node.left)
    postorder_traversal(node.right)
    print(node.val)

# Level order binary tree
  def level_order():
    queue, result = [root], []
    while queue:
      for _ in range(len(queue)):
        curr = queue.pop(0)
        result.append(curr.val)
        if curr.left: queue.append(curr.left)
        if curr.right: queue.append(curr.right)
    return result