code: def test_storage_level():
      level = StorageLevel.DISK | StorageLevel.MEMORY
      assert (
          level == StorageLevel.DISK.value | StorageLevel.MEMORY.value
      )
  
      assert (
          StorageLevel.DISK | StorageLevel.MEMORY
      ) & StorageLevel.DISK
      assert (
          not (StorageLevel.DISK | StorageLevel.MEMORY)
          & StorageLevel.GPU
      )
  
      assert StorageLevel.GPU < StorageLevel.MEMORY < StorageLevel.DISK
      assert StorageLevel.DISK > StorageLevel.MEMORY > StorageLevel.GPU
  
file_path: mars/mars/storage/tests/test_libs.py
imports: import os
  import sys
  import tempfile
  import pkgutil
  import numpy
  import pandas
  import pytest
  import scipy.sparse
  from ...lib.filesystem import LocalFileSystem
  from ...lib.sparse import SparseNDArray, SparseMatrix
  from ...serialization import AioSerializer, AioDeserializer
  from ...tests.core import require_ray, require_cudf, require_cupy
  from ..base import StorageLevel
  from ..cuda import CudaStorage
  from ..filesystem import DiskStorage
  from ..plasma import PlasmaStorage
  from ..shared_memory import SharedMemoryStorage
  from ..vineyard import VineyardStorage
  from ..ray import RayStorage
label_desc: Use image node_id 1 for calling a global function with example usage: test_storage_level() without return types