old_contents: """Classes for binary search tree."""
  
  class Node():
      def __init__(self, value, left=None, right=None):
          """Instantiate a node object."""
          self.value = value
          self.left = left
          self.right = right
  
new_contents: """Classes for binary search tree."""
  
  
  class Node():
      """Node object for the binary search tree."""
  
      def __init__(self, value, left=None, right=None):
          """Instantiate a node object."""
          self.value = value
          self.left = left
          self.right = right
  
  
  class BinarySearchTree():
      """Binary Search Tree.
  
      .insert(): Add a value to the BST
      """
  
      def __init__(self):
          """Initialize the BinarySearchTree Class."""
          self.size = 0
          self.depth = 0
          self.root = None
  
      def insert(self, value):
          """Insert a value in to the binary search tree."""
          if self.root is None:
              self.root = Node(value)
          current_node = self.root
          while True:
              if value < current_node:
                  if current_node.left:
                      current_node = current_node.left
                  else:
                      current_node.left = Node(value)
              if value > current_node:
                  if current_node.right:
                      current_node = current_node.right
                  else:
                      current_node.right = Node(value)
  
subject: insert method for the bst