def next(self):
from data_helpers import next_quarter, quarter_dates, period_for
ns, ne = quarter_dates(*next_quarter(self.quarter, self.year))
return period_for(ns)
def previous(self):
from data_helpers import previous_quarter, quarter_dates, period_for
ns, ne = quarter_dates(*previous_quarter(self.quarter, self.year))
return period_for(ns)
