code: def test_parallel_data_load_from_file_on_main_thread():
      trajectories = [_mock_spaces_trajectory_record(5)] * 10
      with open("trajectories.pkl", "wb") as out_ts:
          pickle.dump(trajectories, out_ts)
  
      dataset = InMemoryDataset(
          n_workers=2,
          conversion_env_factory=None,
          input_data="trajectories.pkl",
          trajectory_processor=IdentityTrajectoryProcessor(),
          deserialize_in_main_thread=True,
      )
  
      assert len(dataset) == 5 * 10
  
imports: import pickle
  from typing import Any, Dict, Union, Tuple, List, Optional
  import gym
  import numpy
  from maze.core.env.maze_action import MazeActionType
  from maze.core.env.maze_state import MazeStateType
  from maze.core.env.structured_env import ActorID
  from maze.core.env.structured_env_spaces_mixin import StructuredEnvSpacesMixin
  from maze.core.log_events.step_event_log import StepEventLog
  from maze.core.trajectory_recording.datasets.trajectory_processor import IdentityTrajectoryProcessor
  from maze.core.trajectory_recording.records.spaces_record import SpacesRecord
  from maze.core.trajectory_recording.records.structured_spaces_record import StructuredSpacesRecord
  from maze.core.trajectory_recording.records.state_record import StateRecord
  from maze.core.trajectory_recording.records.trajectory_record import StateTrajectoryRecord, SpacesTrajectoryRecord
  from maze.core.wrappers.maze_gym_env_wrapper import make_gym_maze_env
  from maze.core.wrappers.wrapper import ObservationWrapper
  from maze.test.shared_test_utils.dummy_env.dummy_core_env import DummyCoreEnvironment
  from maze.test.shared_test_utils.dummy_env.dummy_maze_env import DummyEnvironment
  from maze.test.shared_test_utils.dummy_env.space_interfaces.action_conversion.double import DoubleActionConversion
  from maze.test.shared_test_utils.dummy_env.space_interfaces.observation_conversion.double import DoubleObservationConversion
  from maze.test.shared_test_utils.run_maze_utils import run_maze_job
  from maze.core.trajectory_recording.datasets.in_memory_dataset import InMemoryDataset
label_desc: Use image node_id 10 for calling a global function with example usage: test_parallel_data_load_from_file_on_main_thread() without return types