code: def test_serialize(self):
      config = Config(
          sections=[
              ConfigSection(
                  name="sec1",
                  options=[
                      ConfigOption(key="apache", value="airflow"),
                      ConfigOption(key="hello", value="world"),
                  ],
              ),
              ConfigSection(
                  name="sec2",
                  options=[
                      ConfigOption(key="foo", value="bar"),
                  ],
              ),
          ]
      )
      result = config_schema.dump(config)
      expected = {
          "sections": [
              {
                  "name": "sec1",
                  "options": [
                      {"key": "apache", "value": "airflow"},
                      {"key": "hello", "value": "world"},
                  ],
              },
              {
                  "name": "sec2",
                  "options": [
                      {"key": "foo", "value": "bar"},
                  ],
              },
          ]
      }
      assert result == expected
  
imports: from __future__ import annotations
  from airflow.api_connexion.schemas.config_schema import Config, ConfigOption, ConfigSection, config_schema
label_desc: Use image node_id 1 for calling the TestConfigSchema obj's underlying member method code with example usage: obj.test_serialize() without return types