`transferFlags` too restrictive?
Anything speaking against allowing for incongruent indices in transferFlags field and targets? Cant we just assign to the inner join of their indices? Have some not 100 percent congruent timeseries that share indices over a year but not all throughout their whole extension and i want to bring Flags of one of them to the other.
i know, it could be done with setFlags, but that feels a little annoying syntactically and around the corner, since i have to extract flagged periods indices from one field first, and than pass it as parameter to setFlags..
One could also add a kind of error handling strategy parameter, like in some pandas methods where you have 'coerse' or 'raise'...