Helper function to do operation on sets

        Verify if at least one of the elements
        is present in **kwargs. If no items of rqset
        are contained in **kwargs  the function
        raises exception.

        This check will only trigger if rqset is not empty.

        Raises:
             MissingRequiredCreationParameter

def _minimum_one_is_missing(self, **kwargs):
        """Helper function to do operation on sets

        Verify if at least one of the elements
        is present in **kwargs. If no items of rqset
        are contained in **kwargs  the function
        raises exception.

        This check will only trigger if rqset is not empty.

        Raises:
             MissingRequiredCreationParameter
        """
        rqset = self._meta_data['minimum_additional_parameters']
        if rqset:
            kwarg_set = set(iterkeys(kwargs))
            if kwarg_set.isdisjoint(rqset):
                args = sorted(rqset)
                error_message = 'This resource requires at least one of the ' \
                                'mandatory additional ' \
                                'parameters to be provided: %s' % ', '.join(args)
                raise MissingRequiredCreationParameter(error_message)