code: def test_simple(self):
      def plain(x):
          x.extra = "Hello"
          return x
  
      @plain
      class C(object):
          pass
  
      self.assertEqual(C.extra, "Hello")
  
imports: import unittest
  from types import MethodType
label_desc: Use image node_id 1 for calling the TestClassDecorators obj's underlying member method code with example usage: obj.test_simple() and returns: x