code: def test_add1(self):
      # similar to what IPython is doing in traitlets.config.application
      @decorator
      def add(func, const=1, *args, **kwargs):
          return const + func(*args, **kwargs)
  
      def f(x):
          return x
  
      self.assertEqual(add(f, 2)(0), 2)
  
imports: from __future__ import absolute_import
  import sys
  import doctest
  import unittest
  import decimal
  import inspect
  import functools
  import collections
  from collections import defaultdict
  from decorator import dispatch_on, contextmanager, decorator
label_desc: Use image node_id 6 for calling the ExtraTestCase obj's underlying member method code with example usage: obj.test_add1() and returns: unknown, x