Save configurations of metric. Can be recreated
        from configs with metric.create(``**config``)

def get_config(self):
        """Save configurations of metric. Can be recreated
        from configs with metric.create(``**config``)
        """
        config = self._kwargs.copy()
        config.update({
            'metric': self.__class__.__name__,
            'name': self.name,
            'output_names': self.output_names,
            'label_names': self.label_names})
        return config