pub fn is_exempt(&self) -> bool {
        match self {
            RentDue::Exempt => true,
            RentDue::Paying(_) => false,
        }
    }
/// Return 'true' if rent exempt
Return 'true' if rent exempt
Return ' true ' if rent exempt
pub fn is_exempt(&self) -> bool {
        match self {
            RentDue::Exempt => true,
            RentDue::Paying(_) => false,
        }
    }
pub fn is_exempt ( & self ) -> bool { match self { RentDue :: Exempt => true , RentDue :: Paying ( _ ) => false , } }
Return 'true' if rent exempt
Return ' true ' if rent exempt
&self