code: def open_close(self, testfunc):
      # Open-close template with testfunc called in between.
      opentip = self.ct.open_calltip
      self.text.insert(1.0, "f(")
      opentip(False)
      self.tip = self.ct.active_calltip
      testfunc(self)  ###
      self.text.insert("insert", ")")
      opentip(False)
      self.assertIsNone(self.ct.active_calltip, None)
  
imports: from idlelib import calltip
  import unittest
  from unittest.mock import Mock
  import textwrap
  import types
  import re
  from idlelib.idle_test.mock_tk import Text
  from test.support import MISSING_C_DOCSTRINGS
label_desc: Use image node_id 3 for calling the CalltipTest obj's underlying member method code with example usage: obj.open_close(testfunc) without return types