code: def test__gather_distributed(self, mocker: MockerFixture) -> None:
      mock_is_available = mocker.patch.object(
          dist, "is_available", return_value=True
      )
      MSNLoss(gather_distributed=True)
      mock_is_available.assert_called_once()
  
imports: import unittest
  from unittest import TestCase
  import pytest
  import torch
  import torch.nn.functional
  from pytest_mock import MockerFixture
  from torch import distributed
  from torch import nn
  from torch.optim import SGD
  from lightly.loss import msn_loss
  from lightly.loss.msn_loss import MSNLoss
  from lightly.models.modules.heads import MSNProjectionHead
label_desc: Use image node_id 1 for calling the TestMSNLoss obj's underlying member method code with example usage: obj.test__gather_distributed(mocker) without return types