@abc.abstractmethod<EOL><INDENT>def search_among_commitments(self, commitment_ids):<DEDENT>
pass<EOL>
Execute this search among the given list of commitments.

        :param commitment_ids: list of commitments
        :type commitment_ids: ``osid.id.IdList``
        :raise: ``NullArgument`` -- ``commitment_ids`` is ``null``

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