@abc.abstractmethod<EOL><INDENT>def cardinals_to_strings(self, c):<DEDENT>
return<EOL>
Gets a string representation of an array of cardinals.

        :param c: a cardinal value array
        :type c: ``cardinal[]``
        :return: the display strings
        :rtype: ``string``
        :raise: ``NullArgument`` -- ``c`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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