old_contents: from vega_datasets.core import DataLoader, LocalDataLoader
  data = DataLoader()
  local_data = LocalDataLoader()
  __version__ = '0.4.1'
  
new_contents: from vega_datasets.core import DataLoader, LocalDataLoader
  data = DataLoader()
  local_data = LocalDataLoader()
  __version__ = '0.5.0.dev1'
  
subject: bump version to 0.5.0.dev1