181     @implements_adapter_compat('IDownloadable')

   181     @implements_adapter_compat('IDownloadable')

   182     def download_data(self):

   182     def download_data(self):

   183         """return actual data of the downloadable content"""

   183         """return actual data of the downloadable content"""

   184         raise NotImplementedError

   184         raise NotImplementedError

   185 

   185 

   187 class ITreeAdapter(EntityAdapter):

   187 class ITreeAdapter(EntityAdapter):

   188     """This adapter has to be overriden to be configured using the

   188     """This adapter has to be overriden to be configured using the

   189     tree_relation, child_role and parent_role class attributes to benefit from

   189     tree_relation, child_role and parent_role class attributes to benefit from

   190     this default implementation.

   190     this default implementation.

   191 

   191