code: def test_ssim(reduction_type):
      lossfun = SSimLoss(reduction=reduction_type)
      feats = torch.randn(2, 4, 5)
      lossfun(feats, feats)
  
imports: import pytest
  import torch
  from packaging.version import parse
  from espnet2.tts.prodiff import ProDiff
  from espnet2.tts.prodiff.loss import SSimLoss
label_desc: Use image node_id 2 for calling a global function with example usage: test_ssim(reduction_type) without return types