code: def test_plot_losses(camvid_ds, backbone, monkeypatch):
      monkeypatch.setattr(plt, "show", lambda: None)
      _, ds = camvid_ds
      model = models.fastai.unet.model(
          num_classes=32,
          img_size=64,
          backbone=backbone(pretrained=True),
      )
  
      (
          samples_plus_losses,
          preds,
          _,
      ) = models.fastai.unet.interp.plot_top_losses(
          model=model, dataset=ds, sort_by="loss_unet", n_samples=2
      )
      assert len(samples_plus_losses) == len(ds) == len(preds)
  
      loss_per_image = get_samples_losses(samples_plus_losses)
      assert "filepath" in loss_per_image[0].keys()
  
imports: import pytest
  from icevision.all import *
  from icevision.models.fastai.unet.backbones import *
  from icevision.models.interpretation import get_samples_losses
label_desc: Use image node_id 2 for calling a global function with example usage: test_plot_losses(camvid_ds, backbone, monkeypatch) without return types