Migrate to timedelta/datetime from FiniteDuration/Seconds etc

I am not exactly sure what feels right here, but having our own Seconds doesn't seem too idiomatic.  Perhaps 

date = timedelta(seconds=3)

#or

date = timedelta(milliseconds=100)

 and using that date seems more idiomatic?

The date can always be converted:

date.total_seconds() # a float so feel free to / 1000 or /1000000 for milli or microseconds

Probably there are other possibilities too, thoughts?