Python preferred Time dt syntax? (and some daylights savings..)

Trying to optimize some python code, and learning on the job, i was wondering why:

dt = state.last_changed
dt = dt + datetime.timedelta(hours= 2)

wouldn’t be replace by:

dt = state.last_changed + datetime.timedelta(hours= 2)

any reason the latter would be less robust or desirable ?

also, i was wondering if the obvious daylights savings issue here, (had hours=1 till today…) could be tackled in another way.

Thanks for any insights,