code: def test_string_keys_error(self):
      data = [{"a": "A", "b": (2, 4), "c": 3.0, ("d",): "D tuple"}]
      try:
          json.dumps(data)
      except TypeError:
          err = sys.exc_info()[1]
      else:
          self.fail("Expected TypeError")
      self.assertEqual(
          str(err),
          "keys must be str, int, float, bool or None, not tuple",
      )
  
file_path: catboost/contrib/python/simplejson/py2/simplejson/tests/test_errors.py
imports: import sys, pickle
  from unittest import TestCase
  import simplejson
  from simplejson.compat import text_type, b
label_desc: Use image node_id 1 for calling the TestErrors obj's underlying member method code with example usage: obj.test_string_keys_error() without return types