code: def get_frame(self):
          
          metric_items = list(self.db.metrics.find({'run_name': self.model_config.run_name}).sort('epoch_idx'))
          if len(metric_items) == 0:
              return pd.DataFrame(columns=['run_name'])
          else:
              return pd.DataFrame(metric_items).drop(['_id', 'model_name'], axis=1).set_index('epoch_idx')
docs: Get a dataframe of metrics from this storage