old_contents: from .nnblocks import ConvBlock, UpsampleBlock
  
  __all__ = ['ConvBlock', 'UpsampleBlock']
  
new_contents: from .nnblocks import (ConvBlock, UpsampleBlock, features_to_latent,
                         latent_to_features)
  
  __all__ = ['ConvBlock', 'UpsampleBlock', 'latent_to_features',
             'features_to_latent']
  
subject: Update imports