code: def test_fabric_reference_recursively():
      ensemble = LightningModule()
      inner = LightningModule()
      ensemble.inner = inner
  
      assert inner._fabric is None
  
      fabric = Mock()
      ensemble.fabric = fabric
      # references match
      assert ensemble.fabric is inner.fabric
      # and the fabric was weakly referenced
      assert inner.fabric is weakref.proxy(fabric)
  
imports: import sys
  import weakref
  from unittest.mock import Mock
  import pytest
  import torch
  from lightning.fabric import Fabric
  from lightning.fabric.utilities.imports import _TORCH_GREATER_EQUAL_1_13, _TORCH_GREATER_EQUAL_2_0
  from lightning.pytorch import LightningModule, Trainer
  from lightning.pytorch.core.module import _TrainerFabricShim
  from lightning.pytorch.demos.boring_classes import BoringModel
  from lightning.pytorch.loggers import TensorBoardLogger
  from lightning.pytorch.utilities.exceptions import MisconfigurationException
  from torch import nn
  from torch.optim import SGD, Adam
  from tests_pytorch.helpers.runif import RunIf
label_desc: Use image node_id 18 for calling a global function with example usage: test_fabric_reference_recursively() without return types