code: def listmethods(self):
      if not self.cl:
          return []
      items = []
      for name, lineno in self.cl.methods.items():
          items.append((lineno, name))
      items.sort()
      list = []
      for item, name in items:
          list.append(name)
      return list
  
imports: import os
  import sys
  import pyclbr
  from idlelib import PyShell
  from idlelib.WindowList import ListedToplevel
  from idlelib.TreeWidget import TreeNode, TreeItem, ScrolledCanvas
  from idlelib.configHandler import idleConf
label_desc: Use image node_id 7 for calling the ClassBrowserTreeItem obj's underlying member method code with example usage: obj.listmethods() and returns: list, list