code: def test_context_manager_nesting(self):
      with self.repo.structured_db as db1:
          with self.repo.structured_db as db2:
              db1.create_experiment("exp 1")
              db2.create_experiment("exp 2")
  
      experiment_names = set(
          (exp.name for exp in self.repo.structured_db.experiments())
      )
      expected_names = set(("exp 1", "exp 2"))
      self.assertTrue(experiment_names.issuperset(expected_names))
  
imports: from tests.base import PrefilledDataTestBase
  from aim.sdk.utils import generate_run_hash
label_desc: Use image node_id 3 for calling the TestStructuredDatabase obj's underlying member method code with example usage: obj.test_context_manager_nesting() without return types