code: def test_init(self):
      # test init with list
      foo_dict = NestedDict([(("a", "b"), 1), (("a", "c"), 2)])
      self.assertEqual(foo_dict.asdict(), {"a": {"b": 1, "c": 2}})
  
      # test init with dict
      foo_dict = NestedDict({"a": {"b": 1, "c": 2}})
      self.assertEqual(foo_dict.asdict(), {"a": {"b": 1, "c": 2}})
  
      # test init with NestedDict
      foo_dict = NestedDict(NestedDict({"a": {"b": 1, "c": 2}}))
      self.assertEqual(foo_dict.asdict(), {"a": {"b": 1, "c": 2}})
  
      # test init empty element
      foo_dict = NestedDict({"a": {}})
      self.assertEqual(foo_dict.asdict(), {"a": {}})
  
      # test init with nested empty element
      foo_dict = NestedDict({"a": {"b": {}, "c": 2}})
      self.assertEqual(foo_dict.asdict(), {"a": {"b": {}, "c": 2}})
  
      # test init with empty dict
      self.assertEqual(NestedDict().asdict(), {})
  
file_path: ray/rllib/utils/tests/test_nested_dict.py
imports: import unittest
  from ray.rllib.utils.test_utils import check
  from ray.rllib.utils.nested_dict import NestedDict
label_desc: Use image node_id 3 for calling the TestNestedDict obj's underlying member method code with example usage: obj.test_init() without return types