message: fix empty metrics
diff: @@ -555,7 +555,7 @@ class TableViz(BaseViz):
  m_name = '%' + m
  df[m_name] = pd.Series(metric_percents[m], name=m_name)
  # Remove metrics that are not in the main metrics list
  - metrics = fd.get('metrics', [])
  + metrics = fd.get('metrics') or []
  metrics = [self.get_metric_label(m) for m in metrics]
  for m in filter(
  lambda m: m not in metrics and m in df.columns,
  