def save(self, doc):
        if doc.id:
            return self.update(doc)
        else:
            return self.insert(doc)
def __getattr__(self, name: str) -> Any:
        """Custom __getattr__ to allow access to metrics schema fields."""

        if name not in self._metric_fields:
            raise AttributeError('No field: {} in metrics.'.format(name))

        return self._values[name]