package card type RangeValue int const NoMinimumRange = RangeValue(0) const NoMaximumRange = RangeValue(10) type Range struct { MinimumRange, MaximumRange RangeValue } func (r *Range) MinRange() RangeValue {return r.MinimumRange} func (r *Range) MaxRange() RangeValue {return r.MaximumRange} type HasRange interface { MinRange() RangeValue MaxRange() RangeValue }