code: def test_initialization(self):
      self.assertRaises(
          tkinter.TclError,
          ttk.OptionMenu,
          self.root,
          self.textvar,
          invalid="thing",
      )
  
      optmenu = ttk.OptionMenu(self.root, self.textvar, "b", "a", "b")
      self.assertEqual(optmenu._variable.get(), "b")
  
      self.assertTrue(optmenu["menu"])
      self.assertTrue(optmenu["textvariable"])
  
      optmenu.destroy()
  
imports: import sys
  import unittest
  import Tkinter
  import ttk
  from test.test_support import requires, run_unittest, swap_attr
  from test_ttk.support import AbstractTkTest, destroy_default_root
label_desc: Use image node_id 4 for calling the OptionMenuTest obj's underlying member method code with example usage: obj.test_initialization() without return types