@utilities.arguments_not_none<EOL><INDENT>def assign_equivalent_objective(self, objective_id, equivalent_objective_id):<DEDENT>
raise errors.Unimplemented()<EOL>
Makes an objective equivalent to another objective for the purposes of satisfying a requisite.

        arg:    objective_id (osid.id.Id): the ``Id`` of the principal
                ``Objective``
        arg:    equivalent_objective_id (osid.id.Id): the ``Id`` of the
                equivalent ``Objective``
        raise:  AlreadyExists - ``objective_id`` already mapped to
                ``equiavelnt_objective_id``
        raise:  NotFound - ``objective_id`` or
                ``equivalent_objective_id`` not found
        raise:  NullArgument - ``objective_id`` or
                ``equivalent_objective_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*