fn write_model<W: Write>(&self, writer: &mut W) -> anyhow::Result<()> {

        use crate::model::component::CalendarComponent;

        match self {

            CalendarComponent::Event(component) => {

                writer.write_all(b"BEGIN:VEVENT")?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                for alarm in &component.alarms {

                    writer.write_all(b"\r\n")?;

                    alarm.write_model(writer)?;

                writer.write_all(b"\r\nEND:VEVENT")?;

            CalendarComponent::ToDo(component) => {

                writer.write_all(b"BEGIN:VTODO")?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                for alarm in &component.alarms {

                    writer.write_all(b"\r\n")?;

                    alarm.write_model(writer)?;

                writer.write_all(b"\r\nEND:VTODO")?;

            CalendarComponent::Journal(component) => {

                writer.write_all(b"BEGIN:VJOURNAL")?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                writer.write_all(b"\r\nEND:VJOURNAL")?;

            CalendarComponent::FreeBusy(component) => {

                writer.write_all(b"BEGIN:VFREEBUSY")?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                writer.write_all(b"\r\nEND:VFREEBUSY")?;

            CalendarComponent::TimeZone(component) => {

                writer.write_all(b"BEGIN:VTIMEZONE")?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                for component in &component.components {

                    writer.write_all(b"\r\n")?;

                    component.write_model(writer)?;

                writer.write_all(b"\r\nEND:VTIMEZONE")?;

            CalendarComponent::Standard(component) => {

                writer.write_all(b"BEGIN:STANDARD")?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                writer.write_all(b"\r\nEND:STANDARD")?;

            CalendarComponent::Daylight(component) => {

                writer.write_all(b"BEGIN:DAYLIGHT")?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                writer.write_all(b"\r\nEND:DAYLIGHT")?;

            CalendarComponent::Alarm(component) => {

                writer.write_all(b"BEGIN:VALARM")?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                writer.write_all(b"\r\nEND:VALARM")?;

            CalendarComponent::IanaComponent(component) => {

                writer.write_all(b"BEGIN:")?;

                writer.write_all(component.name.as_bytes())?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                writer.write_all(b"\r\nEND:")?;

                writer.write_all(component.name.as_bytes())?;

            CalendarComponent::XComponent(component) => {

                writer.write_all(b"BEGIN:")?;

                writer.write_all(component.name.as_bytes())?;

                for property in &component.properties {

                    writer.write_all(b"\r\n")?;

                    property.write_model(writer)?;

                writer.write_all(b"\r\nEND:")?;

                writer.write_all(component.name.as_bytes())?;

        Ok(())

    }