@abc.abstractmethod<EOL><INDENT>def get_activities_by_assets(self, asset_ids):<DEDENT>
return<EOL>
Gets the activities for the given asset.

        In plenary mode, the returned list contains all of the
        activities mapped to the asset ``Id`` or an error results if an
        ``Id`` in the supplied list is not found or inaccessible.
        Otherwise, inaccessible ``Activities`` may be omitted from the
        list and may present the elements in any order including
        returning a unique set.

        :param asset_ids: ``Ids`` of ``Assets``
        :type asset_ids: ``osid.id.IdList``
        :return: list of activities
        :rtype: ``osid.learning.ActivityList``
        :raise: ``NotFound`` -- an ``asset_id`` not found
        :raise: ``NullArgument`` -- ``asset_id_list`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

        *compliance: mandatory -- This method is must be implemented.*