code: def test_for_json_encodes_dict_subclass(self):
      self.assertRoundTrip(
          DictForJson(a=1), DictForJson(a=1).for_json()
      )
  
imports: import unittest
  import simplejson
label_desc: Use image node_id 8 for calling the TestForJson obj's underlying member method code with example usage: obj.test_for_json_encodes_dict_subclass() without return types