docstr: Test corner cases in flash_paren_event and paren_closed_event.
  
  These cases force conditional expression and alternate paths.
docstr_tok: ["Test","corner","cases","in","flash_paren_event","and","paren_closed_event",".","These","cases","force","conditional","expression","and","alternate","paths","."]
code: def test_paren_corner(self):
      """
      Test corner cases in flash_paren_event and paren_closed_event.
  
      These cases force conditional expression and alternate paths.
      """
      text = self.text
      pm = ParenMatch(self.editwin)
  
      text.insert("insert", "# this is a commen)")
      self.assertIsNone(pm.paren_closed_event("event"))
  
      text.insert("insert", "\ndef")
      self.assertIsNone(pm.flash_paren_event("event"))
      self.assertIsNone(pm.paren_closed_event("event"))
  
      text.insert("insert", " a, *arg)")
      self.assertIsNone(pm.paren_closed_event("event"))
  
file_path: catboost/contrib/tools/python/src/Lib/idlelib/idle_test/test_parenmatch.py
imports: import unittest
  from test.test_support import requires
  from Tkinter import Tk, Text
  from idlelib.ParenMatch import ParenMatch
label_desc: Use image node_id 6 for calling the ParenMatchTest obj's underlying member method code with example usage: obj.test_paren_corner() without return types