code: def test_join(self):
      join = tkinter._join
      tcl = self.interp.tk
  
      def unpack(s):
          return tcl.call("lindex", s, 0)
  
      def check(value):
          self.assertEqual(unpack(join([value])), value)
          self.assertEqual(unpack(join([value, 0])), value)
          self.assertEqual(unpack(unpack(join([[value]]))), value)
          self.assertEqual(unpack(unpack(join([[value, 0]]))), value)
          self.assertEqual(unpack(unpack(join([[value], 0]))), value)
          self.assertEqual(unpack(unpack(join([[value, 0], 0]))), value)
  
      check("")
      check("spam")
      check("sp am")
      check("sp\tam")
      check("sp\nam")
      check(" \t\n")
      check("{spam}")
      check("{sp am}")
      check('"spam"')
      check('"sp am"')
      check('{"spam"}')
      check('"{spam}"')
      check("sp\\am")
      check('"sp\\am"')
      check('"{}" "{}"')
      check('"\\')
      check('"{')
      check('"}')
      check("\n\\")
      check("\n{")
      check("\n}")
      check("\\\n")
      check("{\n")
      check("}\n")
  
imports: import unittest
  import subprocess
  import sys
  import os
  from test import support
  from test.support import import_helper
  from test.support import os_helper
  import tkinter
  from tkinter import Tcl
  from _tkinter import TclError
label_desc: Use image node_id 39 for calling the TclTest obj's underlying member method code with example usage: obj.test_join() and returns: tcl