code: def test_list_trials_without_experiment_name(
      sagemaker_session, datetime_obj
  ):
      client = sagemaker_session.sagemaker_client
      client.list_trials.return_value = {
          "TrialSummaries": [
              {
                  "TrialName": "trial-1",
                  "CreationTime": datetime_obj,
                  "LastModifiedTime": datetime_obj,
              },
              {
                  "TrialName": "trial-2",
                  "CreationTime": datetime_obj,
                  "LastModifiedTime": datetime_obj,
              },
          ]
      }
      expected = [
          TrialSummary(
              trial_name="trial-1",
              creation_time=datetime_obj,
              last_modified_time=datetime_obj,
          ),
          TrialSummary(
              trial_name="trial-2",
              creation_time=datetime_obj,
              last_modified_time=datetime_obj,
          ),
      ]
      assert expected == list(
          _Trial.list(sagemaker_session=sagemaker_session)
      )
      client.list_trials.assert_called_with(**{})
  
imports: from __future__ import absolute_import
  import botocore
  import pytest
  import datetime
  from unittest.mock import patch
  from sagemaker import Session
  from sagemaker.experiments._api_types import TrialSummary
  from sagemaker.experiments.trial import _Trial
  from sagemaker.experiments.trial_component import _TrialComponent
label_desc: Use image node_id 11 for calling a global function with example usage: test_list_trials_without_experiment_name(sagemaker_session, datetime_obj) without return types