readme: !pip install -Uqq fastbook
  !pip install fastai==2.5
  import fastbook
  fastbook.setup_book()
  
  from fastbook import *
  from fastai.vision.widgets import *
  
  path = Path('/content/gdrive/My Drive/caballos')
  
  modelo = DataBlock(
      blocks=(ImageBlock, CategoryBlock), 
      get_items=get_image_files, 
      splitter=RandomSplitter(valid_pct=0.2, seed=42),
      get_y=parent_label,
      item_tfms=RandomResizedCrop(224, min_scale=0.5),
      batch_tfms=aug_transforms())
  
  dls = modelo.dataloaders(path)
  
  learn = cnn_learner(dls, resnet18, metrics=error_rate)
  learn.fine_tune(4)