For durations, we were using calamine's as_time API to convert durations to milliseconds, as the as_duration API was not available at the time of implementation. However, this does not work anymore, as as_time will return None for Duration values. This fixes it
closes #159
For durations, we were using calamine's as_time API to convert durations to milliseconds, as the as_duration API was not available at the time of implementation. However, this does not work anymore, as as_time will return None for Duration values. This fixes it