@utilities.arguments_not_none<EOL><INDENT>def get_child_objective_ids(self, objective_id):<DEDENT>
raise errors.Unimplemented()<EOL>
Gets the child ``Ids`` of the given objective.

        arg:    objective_id (osid.id.Id): the ``Id`` to query
        return: (osid.id.IdList) - the children of the objective
        raise:  NotFound - ``objective_id`` is not found
        raise:  NullArgument - ``objective_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*