fix: type hint

fgpyo/util/metric.py

@@ -200,7 +200,7 @@ def formatted_values(self) -> List[str]:
  """An iterator over formatted attribute values in the same order as the header."""
  return [self.format_value(value) for value in self.values()]
 
- def formatted_items(self) -> List[str]:
+ def formatted_items(self) -> List[Tuple[str, str]]:
  """An iterator over formatted attribute values in the same order as the header."""
  return [(key, self.format_value(value)) for key, value in self.items()]