code: def test_parse_foo_default(self) -> None:
      raw_config = {}
      config = Config(**raw_config)
      self.assertEqual(config.union.value.foo(), 2)
  
imports: import abc
  import os
  import unittest
  from reagent.core.configuration import make_config_class, resolve_defaults
  from reagent.core.dataclasses import dataclass, field
  from reagent.core.registry_meta import RegistryMeta
  from reagent.core.tagged_union import TaggedUnion
label_desc: Use image node_id 1 for calling the TestConfigParsing obj's underlying member method code with example usage: obj.test_parse_foo_default() without return types