code: def test_fastai_unet_train(camvid_ds, backbone):
      train_ds, valid_ds = camvid_ds
      train_dl = models.fastai.unet.train_dl(
          train_ds, batch_size=4, num_workers=0, shuffle=False
      )
      valid_dl = models.fastai.unet.valid_dl(
          valid_ds, batch_size=1, num_workers=0, shuffle=False
      )
      model = models.fastai.unet.model(
          num_classes=32,
          img_size=64,
          backbone=backbone(pretrained=False),
      )
  
      class LightModel(models.fastai.unet.lightning.ModelAdapter):
          def configure_optimizers(self):
              return Adam(self.parameters(), lr=1e-4)
  
      light_model = LightModel(model)
  
      trainer = pl.Trainer(
          max_epochs=1,
          enable_model_summary=False,
          num_sanity_val_steps=0,
          logger=False,
          enable_checkpointing=False,
      )
      trainer.fit(light_model, train_dl, valid_dl)
  
imports: import pytest
  from icevision.all import *
  from icevision.models.fastai.unet.backbones import *
label_desc: Use image node_id 1 for calling a global function with example usage: test_fastai_unet_train(camvid_ds, backbone) and returns: Adam