@utilities.arguments_not_none<EOL><INDENT>def get_equivalent_objectives(self, objective_id):<DEDENT>
raise errors.Unimplemented()<EOL>
Gets a list of ``Objectives`` that are equivalent to the given ``Objective`` for the purpose of requisites.

        An equivalent objective can satisfy the given objective. In
        plenary mode, the returned list contains all of the equivalent
        requisites, or an error results if an Objective is not found or
        inaccessible. Otherwise, inaccessible ``Objectives`` may be
        omitted from the list and may present the elements in any order
        including returning a unique set.

        arg:    objective_id (osid.id.Id): ``Id`` of the ``Objective``
        return: (osid.learning.ObjectiveList) - the returned
                ``Objective`` list
        raise:  NotFound - ``objective_id`` 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.*