class_docstr: Tests for Importer and derived classes.
code: def test_sys_importer(self):
      import package_a
      import package_a.subpackage
  
      self.assertIs(sys_importer.import_module("package_a"), package_a)
      self.assertIs(
          sys_importer.import_module("package_a.subpackage"),
          package_a.subpackage,
      )
  
file_path: pytorch/test/package/test_importer.py
imports: from io import BytesIO
  import torch
  from torch.package import Importer, OrderedImporter, PackageExporter, PackageImporter, sys_importer
  from torch.testing._internal.common_utils import run_tests
label_desc: Use image node_id 1 for calling the TestImporter obj's underlying member method code with example usage: obj.test_sys_importer() without return types