Insert into a BST Python

gistfile1.py

def insert(root, node):
  curr = root # Keeps the root of the tree.
  while curr:
    parent = curr
    if node.key < curr.key:
      curr = node.left
    else:
      curr = node.right
  node.parent = parent
  if node.parent is None:
    return node # New root of an empty tree.
  if node.key < node.parent.key:
    node.parent.left = node
  else
    node.parent.rigth = node
  return root # Returns the root of the tree.