Error during 1-simple lap

[Ripa00]

Hi Juan,
i'm trying to run the 1 simple lap, but at the end when i write the last row
run = fastest_lap.download_variables(*fastest_lap.optimal_laptime(vehicle_name, track_name, s, options))

this error shows up

[C++ exception] -> std::bad_cast
terminate called after throwing an instance of 'std::exception'
what(): std::exception
Aborted

how can i fix it??
Thank you and congratulations for this software