code: def expand(self, event=None):
      if not self.item._IsExpandable():
          return
      if self.state != "expanded":
          self.state = "expanded"
          self.update()
          self.view()
  
imports: import os
  from tkinter import *
  from tkinter.ttk import Frame, Scrollbar
  from idlelib.config import idleConf
  from idlelib import zoomheight
label_desc: Use image node_id 9 for calling the TreeNode obj's underlying member method code with example usage: obj.expand(event) without return types