code: def test_missing_value(self):
      config_json = json.loads(
          """
              {}
          """
      )
      self.assertRaises(
          MissingValueError, config_from_json, Model2, config_json
      )
  
imports: import json
  import unittest
  from typing import List, Tuple, Union
  from pytext.config.component import Component, ComponentType
  from pytext.config.pytext_config import ConfigBase
  from pytext.config.serialize import config_from_json, config_to_json, ConfigParseError, MissingValueError, UnionTypeError
label_desc: Use image node_id 8 for calling the PytextConfigTest obj's underlying member method code with example usage: obj.test_missing_value() without return types