code: def stats(self) -> pd.DataFrame:
          
          cumul = []
          for f in self:
              info = {
                  "flight_id": f.flight_id,
                  "callsign": f.callsign,
                  "origin": f.origin,
                  "destination": f.destination,
                  "duration": f.stop - f.start,  # type: ignore
              }
              cumul.append(info)
  
          return (
              pd.DataFrame.from_records(cumul)
              .set_index("flight_id")
              .sort_values("duration", ascending=False)
          )
docs: Statistics about flights contained in the structure.
          Useful for a meaningful representation.