@abc.abstractmethod<EOL><INDENT>def is_equivalent(self, id_, equivalent_id):<DEDENT>
return<EOL>
Tests if the two ``Ids`` are equivalent.

        Two ``Ids`` are equivalent if they identify the same object. If
        one of the ``Ids`` is not known, they are not equivalent.

        :param id: an ``Id``
        :type id: ``osid.id.Id``
        :param equivalent_id: an ``Id``
        :type equivalent_id: ``osid.id.Id``
        :return: ``true`` if the ``Ids`` are equivalent, false otherwise
        :rtype: ``boolean``
        :raise: ``NullArgument`` -- ``null`` argument provided
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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