code: def test_invalid_execution_date_raises(self):
      serialized_dagrun = {"execution_date": "mydate"}
      with pytest.raises(BadRequest) as ctx:
          dagrun_schema.load(serialized_dagrun)
      assert str(ctx.value) == "Incorrect datetime argument"
  
imports: from __future__ import annotations
  import pytest
  from dateutil.parser import parse
  from airflow.api_connexion.exceptions import BadRequest
  from airflow.api_connexion.schemas.dag_run_schema import DAGRunCollection, dagrun_collection_schema, dagrun_schema
  from airflow.models import DagRun
  from airflow.utils import timezone
  from airflow.utils.session import provide_session
  from airflow.utils.types import DagRunType
  from tests.test_utils.db import clear_db_runs
label_desc: Use image node_id 4 for calling the TestDAGRunSchema obj's underlying member method code with example usage: obj.test_invalid_execution_date_raises() without return types