Inspects config and sets the name of the formatter to either "json" or "text"
        as instance attr. If not present in config, default is "text"

def _set_formatter(self):
        """
        Inspects config and sets the name of the formatter to either "json" or "text"
        as instance attr. If not present in config, default is "text"
        """
        if hasattr(self._config, "formatter") and self._config.formatter == "json":
            self._formatter = "json"
        else:
            self._formatter = "text"