code: def test_get_null(self):
      v = StringVar(self.root, "abc\x00def", "name")
      self.assertEqual("abc\x00def", v.get())
      self.root.globalsetvar("name", "val\x00ue")
      self.assertEqual("val\x00ue", v.get())
  
imports: import unittest
  from test import support
  import gc
  import tkinter
  from tkinter import Variable, StringVar, IntVar, DoubleVar, BooleanVar, Tcl, TclError
  from test.support import ALWAYS_EQ
  from test.test_tkinter.support import AbstractDefaultRootTest
label_desc: Use image node_id 3 for calling the TestStringVar obj's underlying member method code with example usage: obj.test_get_null() without return types