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

        :param proficiency_ids: list of proficiencies
        :type proficiency_ids: ``osid.id.IdList``
        :raise: ``NullArgument`` -- ``proficiency_ids`` is ``null``

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