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, TransactionClause):
                raise QueryException('{} is not a valid query operator'.format(operator))
            clone._transaction.append(operator)

        for col_name, val in kwargs.items():
            exists = False
            try:
                column = self.model._get_column(col_name)
            except KeyError:
                if col_name == 'pk__token':
                    if not isinstance(val, Token):
                        raise QueryException("Virtual column 'pk__token' may only be compared to Token() values")
                    column = columns._PartitionKeysToken(self.model)
                    quote_field = False
                else:
                    raise QueryException("Can't resolve column name: '{}'".format(col_name))

            if isinstance(val, Token):
                if col_name != 'pk__token':
                    raise QueryException("Token() values may only be compared to the 'pk__token' virtual column")
                partition_columns = column.partition_columns
                if len(partition_columns) != len(val.value):
                    raise QueryException(
                        'Token() received {} arguments but model has {} partition keys'.format(
                            len(val.value), len(partition_columns)))
                val.set_columns(partition_columns)

            if isinstance(val, BaseQueryFunction) or exists is True:
                query_val = val
            else:
                query_val = column.to_database(val)

            clone._transaction.append(TransactionClause(col_name, query_val))

        return clone