old_contents: from pkg_resources import get_distribution
  from serfclient.client import SerfClient
  
  __version__ = get_distribution('serfclient').version
  
new_contents: from pkg_resources import get_distribution
  from serfclient.client import SerfClient
  
  __version__ = get_distribution('serfclient').version
  
  __all__ = ['SerfClient']
  
subject: Add __all__