Set a fallback range for reports

[oivvio]

I just started using timewarrior and the first thing I did was import 10+ years of data from my old home grown time tracking system.

I'd like to be able to set a default time range that is used if no other range is given. That way my extensions could default to looking at say the last 6 months of data instead of looking at everything I ever done.

timew summary defaults to :day but I can't find I way to override that or set a default for other operations.