def _prepare_query_values(self):
        """Extra prep on query values by converting
        dictionaries into :see:HStoreValue expressions.

        This allows putting expressions in a dictionary.
        The :see:HStoreValue will take care of resolving
        the expressions inside the dictionary."""

        new_query_values = []
        for field, model, val in self.query.values:
            if isinstance(val, dict):
                val = HStoreValue(val)

            new_query_values.append((
                field,
                model,
                val
            ))

        self.query.values = new_query_values