def iff(self, *args, **kwargs):
        """Adds IF statements to queryset"""
        if len([x for x in kwargs.values() if x is None]):
            raise CQLEngineException("None values on iff are not allowed")

        clone = copy.deepcopy(self)
        for operator in args:
            if not isinstance(operator, ConditionalClause):
                raise QueryException('{0} is not a valid query operator'.format(operator))
            clone._conditional.append(operator)

        for arg, val in kwargs.items():
            if isinstance(val, Token):
                raise QueryException("Token() values are not valid in conditionals")

            col_name, col_op = self._parse_filter_arg(arg)
            try:
                column = self.model._get_column(col_name)
            except __HOLE__:
                raise QueryException("Can't resolve column name: '{0}'".format(col_name))

            if isinstance(val, BaseQueryFunction):
                query_val = val
            else:
                query_val = column.to_database(val)

            operator_class = BaseWhereOperator.get_operator(col_op or 'EQ')
            operator = operator_class()
            clone._conditional.append(WhereClause(column.db_field_name, operator, query_val))

        return clone
dataset/ETHPy150Open datastax/python-driver/cassandra/cqlengine/query.py/AbstractQuerySet.iff