def maybe_convert_values(self,
                             identifier: Identifier,
                             data: Dict[str, Any],
                             ) -> Dict[str, Any]:
        """
        Takes a dictionary of raw values for a specific identifier, as parsed
        from the YAML file, and depending upon the type of db column the data
        is meant for, decides what to do with the value (eg leave it alone,
        convert a string to a date/time instance, or convert identifiers to
        model instances by calling :meth:`self.loader.convert_identifiers`)

        :param identifier: An object with :attr:`class_name` and :attr:`key`
                           attributes
        :param data: A dictionary keyed by column name, with values being the
                     raw values as parsed from the YAML
        :return: A dictionary keyed by column name, with values being the
                 converted values meant to be set on the model instance
        """
        raise NotImplementedError
Takes a dictionary of raw values for a specific identifier, as parsed
        from the YAML file, and depending upon the type of db column the data
        is meant for, decides what to do with the value (eg leave it alone,
        convert a string to a date/time instance, or convert identifiers to
        model instances by calling :meth:`self.loader.convert_identifiers`)

        :param identifier: An object with :attr:`class_name` and :attr:`key`
                           attributes
        :param data: A dictionary keyed by column name, with values being the
                     raw values as parsed from the YAML
        :return: A dictionary keyed by column name, with values being the
                 converted values meant to be set on the model instance