old_contents: 
  VERSION = (0, 4, 1)
  
new_contents: 
  VERSION = (0, 4, 1, 'pre')
  
  def register(*args, **kwargs):
      """
      Registers a model class as an MPTTModel, adding MPTT fields and adding MPTTModel to __bases__.
      This is equivalent to just subclassing MPTTModel, but works for an already-created model.
      
      This method was removed in 0.4.0, but restored in 0.4.2 after use-cases were
      reported that were impossible by merely subclassing MPTTModel.
      """
      from mptt.models import MPTTModelBase
      return MPTTModelBase.register(*args, **kwargs)
  
subject: add mptt.register() back in after use cases were reported making it neccessary sometimes, and after finding it's not actually too hard to do. 0.4.2 candidate pending resolution of comments on gh-19