docs: def get_bin_hierarchy_design_session(self):
          """Gets the bin hierarchy design session.
  
          return: (osid.resource.BinHierarchyDesignSession) - a
                  ``BinHierarchyDesignSession``
          raise:  OperationFailed - unable to complete request
          raise:  Unimplemented - ``supports_bin_hierarchy_design()`` is
                  ``false``
          *compliance: optional -- This method must be implemented if
          ``supports_bin_hierarchy_design()`` is ``true``.*
  
          """
          if not self.supports_bin_hierarchy_design():
              raise errors.Unimplemented()
          # pylint: disable=no-member
          return sessions.BinHierarchyDesignSession(runtime=self._runtime)