new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  
  class Binary(object):
      def __init__(self, root):
          self.key = root
          self.left_child = None
          self.right_child = None
  
      def insert_left(self, new_node):
          if self.left_child is None:
              self.left_child = Binary(new_node)
          else:
              t = Binary(new_node)
              t.left_child = self.left_child
              self.left_child = t
  
      def insert_right(self, new_node):
          if self.right_child is None:
              self.right_child = Binary(new_node)
          else:
              t = Binary(new_node)
              t.right_child = self.right_child
              self.right_child = t
  
      def get_value(self):
          return self.key
  
  if __name__ == "__main__":
      b = Binary("test")
      print b.left_child, b.right_child
      b.insert_left("1left")
      print b.left_child, b.right_child
      b.insert_left("1right")
      print b.left_child.left_child, b.right_child
  
  
subject: add tree with python