code: def test_serialize(self, session):
      connection_model = Connection(
          conn_id="mysql_default",
          conn_type="mysql",
          host="mysql",
          login="login",
          schema="testschema",
          port=80,
      )
      session.add(connection_model)
      session.commit()
      connection_model = session.query(Connection).first()
      deserialized_connection = connection_collection_item_schema.dump(
          connection_model
      )
      assert deserialized_connection == {
          "connection_id": "mysql_default",
          "conn_type": "mysql",
          "description": None,
          "host": "mysql",
          "login": "login",
          "schema": "testschema",
          "port": 80,
      }
  
imports: from __future__ import annotations
  import re
  import marshmallow
  import pytest
  from airflow.api_connexion.schemas.connection_schema import ConnectionCollection, connection_collection_item_schema, connection_collection_schema, connection_schema, connection_test_schema
  from airflow.models import Connection
  from airflow.utils.session import create_session, provide_session
  from tests.test_utils.db import clear_db_connections
label_desc: Use image node_id 3 for calling the TestConnectionCollectionItemSchema obj's underlying member method code with example usage: obj.test_serialize(session) without return types