# File lib/ice_cube/validations/daily_interval.rb, line 33
      def validate(step_time, start_time)
        t0, t1 = start_time, step_time
        days = Date.new(t1.year, t1.month, t1.day) -
               Date.new(t0.year, t0.month, t0.day)
        offset = (days % interval).nonzero?
        interval - offset if offset
      end