diff --git a/pmoupnp/errors.rs b/pmoupnp/errors.rs
new file mode 100644
index 00000000..f34f65a0
--- /dev/null
+++ b/pmoupnp/errors.rs
@@ -0,0 +1,72 @@
+use thiserror::Error;
+
+
+
+#[derive(Error, Debug)]
+pub enum StateVariableError {
+    #[error("Conversion error: {0}")]
+    ConversionError(String),
+    
+    #[error("Validation error: {0}")]
+    ValidationError(String),
+    
+    #[error("Range error: {0}")]
+    RangeError(String),
+    
+    #[error("Type error: {0}")]
+    TypeError(String),
+    
+    #[error("Parse error: {0}")]
+    ParseError(String),
+    
+    #[error("Event condition error: {0}")]
+    EventConditionError(String),
+    
+    #[error("Arithmetic error: {0}")]
+    ArithmeticError(String),
+    
+    #[error("Unknown error: {0}")]
+    Unknown(String),
+}
+
+impl From<std::num::TryFromIntError> for StateVariableError {
+    fn from(err: std::num::TryFromIntError) -> Self {
+        StateVariableError::ConversionError(format!("Integer conversion error: {}", err))
+    }
+}
+
+impl From<std::str::ParseBoolError> for StateVariableError {
+    fn from(err: std::str::ParseBoolError) -> Self {
+        StateVariableError::ConversionError(format!("Boolean conversion error: {}", err))
+    }
+}
+
+impl From<uuid::Error> for StateVariableError {
+    fn from(err: uuid::Error) -> Self {
+        StateVariableError::ConversionError(format!("UUID conversion error: {}", err))
+    }
+}
+
+impl From<chrono::ParseError> for StateVariableError {
+    fn from(err: chrono::ParseError) -> Self {
+        StateVariableError::ConversionError(format!("Time conversion error: {}", err))
+    }
+}
+
+impl From<url::ParseError> for StateVariableError {
+    fn from(err: url::ParseError) -> Self {
+        StateVariableError::ConversionError(format!("URI conversion error: {}", err))
+    }
+}
+
+impl From<base64::DecodeError> for StateVariableError {
+    fn from(err: base64::DecodeError) -> Self {
+        StateVariableError::ConversionError(format!("Base64 conversion error: {}", err))
+    }
+}
+
+impl From<hex::FromHexError> for StateVariableError {
+    fn from(err: hex::FromHexError) -> Self {
+        StateVariableError::ConversionError(format!("Hex conversion error: {}", err))
+    }
+}
diff --git a/pmoupnp/src/actions/action_instance.rs b/pmoupnp/src/actions/action_instance.rs
new file mode 100644
index 00000000..a4de2140
--- /dev/null
+++ b/pmoupnp/src/actions/action_instance.rs
@@ -0,0 +1,51 @@
+use xmltree::{Element, XMLNode};
+
+use crate::actions::Action;
+use crate::actions::Argument;
+use crate::actions::ArgumentSet;
+use crate::actions::ActionInstance;
+use crate::UpnpXml;
+use crate::{UpnpObject, UpnpObjectType};
+
+impl UpnpXml for ActionInstance {
+fn to_xml_element(&self) -> Element {
+        let mut elem = Element::new("action");
+
+        // <name>
+        let mut name_elem = Element::new("name");
+        name_elem.children.push(XMLNode::Text(self.get_name().clone()));
+        elem.children.push(XMLNode::Element(name_elem));
+
+        // déplacer tous les enfants de args_elem dans un nouvel Element
+        let args_container = self.arguments_set().to_xml_element();
+        elem.children.push(XMLNode::Element(args_container));
+
+        elem
+    }  
+}
+impl UpnpObject for ActionInstance {
+    fn as_upnp_object_type(&self) -> &UpnpObjectType {
+        return &self.object;
+    }
+}
+
+impl ActionInstance {
+
+    pub fn new(action: &Action) -> Self {
+        Self {
+            object: UpnpObjectType {
+                name: action.get_name().clone(),
+                object_type: "ActionInstance".to_string(),
+            },
+            model: action.clone(),
+        }
+    }
+
+    pub fn arguments(&self, name: &str) -> Option<&Argument> {
+        self.model.arguments.get(name)
+    }
+
+    pub fn arguments_set(&self) -> &ArgumentSet {
+        &self.model.arguments
+    }
+}
diff --git a/pmoupnp/src/actions/action_instance_set.rs b/pmoupnp/src/actions/action_instance_set.rs
new file mode 100644
index 00000000..02583e3f
--- /dev/null
+++ b/pmoupnp/src/actions/action_instance_set.rs
@@ -0,0 +1,49 @@
+use crate::{
+    UpnpObject, UpnpXml,
+    actions::{ActionInstance, ActionInstanceSet},
+};
+use std::collections::HashMap;
+use xmltree::{Element,XMLNode};
+
+impl UpnpXml for ActionInstanceSet {
+    // Méthode pour convertir en XML (à implémenter avec une librairie XML)
+    fn to_xml_element(&self) -> Element {
+        let mut elem = Element::new("actionList");
+
+        for action in self.iter() {
+            let action_elem = action.to_xml_element(); // retourne un <action> complet
+            elem.children.push(XMLNode::Element(action_elem));
+        }
+
+        elem
+    }
+}
+
+impl ActionInstanceSet {
+    pub fn new() -> Self {
+        Self {
+            instances: HashMap::new(),
+        }
+    }
+
+    pub fn insert(&mut self, instance: ActionInstance) {
+        self.instances.insert(instance.get_name().clone(), instance);
+    }
+
+    pub fn contains(&self, name: &str) -> bool {
+        self.instances.contains_key(name)
+    }
+
+    pub fn get(&self, name: &str) -> Option<&ActionInstance> {
+        self.instances.get(name)
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &ActionInstance> {
+        self.instances.values()
+    }
+
+    pub fn all(&self) -> Vec<&ActionInstance> {
+        self.instances.values().collect()
+    }
+}
+
diff --git a/pmoupnp/src/actions/action_methods.rs b/pmoupnp/src/actions/action_methods.rs
new file mode 100644
index 00000000..4b9bd0ea
--- /dev/null
+++ b/pmoupnp/src/actions/action_methods.rs
@@ -0,0 +1,51 @@
+use xmltree::{Element,XMLNode};
+
+use crate::UpnpXml;
+use crate::actions::Action;
+use crate::actions::Argument;
+use crate::actions::ArgumentSet;
+use crate::{UpnpObject, UpnpObjectType};
+
+impl UpnpXml for Action {
+    fn to_xml_element(&self) -> Element {
+        let mut action_elem = Element::new("action");
+
+        // <name>
+        let mut name_elem = Element::new("name");
+        name_elem
+            .children
+            .push(XMLNode::Text(self.get_name().clone()));
+        action_elem.children.push(XMLNode::Element(name_elem));
+
+        // <argumentList>
+        let args_elem = self.arguments.to_xml_element();
+        action_elem.children.push(XMLNode::Element(args_elem));
+
+        action_elem
+    }
+}
+impl UpnpObject for Action {
+    fn as_upnp_object_type(&self) -> &UpnpObjectType {
+        return &self.object;
+    }
+}
+
+impl Action {
+    pub fn new(name: String) -> Action {
+        Self {
+            object: UpnpObjectType {
+                name,
+                object_type: "Action".to_string(),
+            },
+            arguments: ArgumentSet::new(),
+        }
+    }
+
+    pub fn add_argument(&mut self, arg: Argument) {
+        self.arguments.insert(arg);
+    }
+
+    pub fn arguments(&self) -> &ArgumentSet {
+        &self.arguments
+    }
+}
diff --git a/pmoupnp/src/actions/action_set_methods.rs b/pmoupnp/src/actions/action_set_methods.rs
new file mode 100644
index 00000000..3113b1dc
--- /dev/null
+++ b/pmoupnp/src/actions/action_set_methods.rs
@@ -0,0 +1,61 @@
+use std::collections::HashMap;
+use xmltree::{Element, XMLNode};
+
+use crate::actions::Action;
+use crate::actions::ActionSet;
+use crate::actions::errors::ActionError;
+use crate::UpnpObject;
+use crate::UpnpXml;
+
+impl UpnpXml for ActionSet {
+         fn to_xml_element(&self) -> Element {
+        let mut elem = Element::new("actionList");
+
+        for action in self.iter() {
+            let action_elem = action.to_xml_element(); // retourne un <action> complet
+            elem.children.push(XMLNode::Element(action_elem));
+        }
+
+        elem
+    }
+
+}
+
+impl ActionSet {
+    pub fn new() -> Self {
+        Self {
+            actions: HashMap::new(),
+        }
+    }
+
+    pub fn insert(&mut self, action: Action) -> Result<(), ActionError> {
+        let name = action.get_name();
+        if self.actions.contains_key(name) {
+            return Err(ActionError::SetError(
+                format!("Action {} already exists", name)
+            ));
+        }
+        self.actions.insert(name.clone(), action);
+        Ok(())
+    }
+
+    pub fn insert_or_replace(&mut self, action: Action) {
+        self.actions.insert(action.get_name().clone(), action);
+    }
+
+    pub fn contains(&self, name: &str) -> bool {
+        self.actions.contains_key(name)
+    }
+
+    pub fn get(&self, name: &str) -> Option<&Action> {
+        self.actions.get(name)
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &Action> {
+        self.actions.values()
+    }
+
+    pub fn all(&self) -> Vec<&Action> {
+        self.actions.values().collect()
+    }
+}
diff --git a/pmoupnp/src/actions/arg_set_methods.rs b/pmoupnp/src/actions/arg_set_methods.rs
new file mode 100644
index 00000000..0212677f
--- /dev/null
+++ b/pmoupnp/src/actions/arg_set_methods.rs
@@ -0,0 +1,52 @@
+use crate::UpnpObject;
+use crate::{
+    UpnpXml,
+    actions::{Argument, ArgumentSet},
+};
+use std::collections::HashMap;
+use xmltree::Element;
+
+impl UpnpXml for ArgumentSet {
+    // Méthode pour convertir en XML (à implémenter avec une librairie XML)
+    fn to_xml_element(&self) -> Element {
+        let mut elem = Element::new("argumentList");
+
+        for arg in self.iter() {
+            let arg_elem = arg.to_xml_element(); // toujours un <argumentList> contenant 1 ou 2 <argument>
+
+            // Pour InOut, on ajoute tous les enfants du <argumentList> généré
+            for child in arg_elem.children {
+                elem.children.push(child);
+            }
+        }
+
+        elem
+    }
+}
+impl ArgumentSet {
+    pub fn new() -> Self {
+        Self {
+            arguments: HashMap::new(),
+        }
+    }
+
+    pub fn insert(&mut self, arg: Argument) {
+        self.arguments.insert(arg.get_name().clone(), arg);
+    }
+
+    pub fn contains(&self, name: &str) -> bool {
+        self.arguments.contains_key(name)
+    }
+
+    pub fn get(&self, name: &str) -> Option<&Argument> {
+        self.arguments.get(name)
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &Argument> {
+        self.arguments.values()
+    }
+
+    pub fn all(&self) -> Vec<&Argument> {
+        self.arguments.values().collect()
+    }
+}
diff --git a/pmoupnp/src/actions/argument.rs b/pmoupnp/src/actions/argument.rs
new file mode 100644
index 00000000..de75c244
--- /dev/null
+++ b/pmoupnp/src/actions/argument.rs
@@ -0,0 +1,108 @@
+use xmltree::{Element, XMLNode};
+
+use crate::{
+    UpnpObject, UpnpObjectType, UpnpXml, actions::Argument, state_variables::StateVariable,
+};
+
+impl UpnpXml for Argument {
+    fn to_xml_element(&self) -> Element {
+        let mut parent = Element::new("argumentList");
+
+        if self.is_in() && self.is_out() {
+            // InOut → deux arguments
+            parent.children.push(XMLNode::Element(make_argument_elem(
+                self.get_name(),
+                "in",
+                self.state_variable().get_name(),
+            )));
+            parent.children.push(XMLNode::Element(make_argument_elem(
+                self.get_name(),
+                "out",
+                self.state_variable().get_name(),
+            )));
+        } else {
+            // Cas simple
+            let direction = if self.is_in() { "in" } else { "out" };
+            parent.children.push(XMLNode::Element(make_argument_elem(
+                self.get_name(),
+                direction,
+                self.state_variable().get_name(),
+            )));
+        }
+
+        parent
+    }
+}
+
+impl UpnpObject for Argument {
+    fn as_upnp_object_type(&self) -> &UpnpObjectType {
+        return &self.object;
+    }
+}
+
+impl Argument {
+    fn new(name: String, state_variable: StateVariable) -> Self {
+        Self {
+            object: UpnpObjectType {
+                name,
+                object_type: "Argument".to_string(),
+            },
+            state_variable,
+            is_in: false,
+            is_out: false,
+        }
+    }
+
+    pub fn new_in(name: String, state_variable: StateVariable) -> Self {
+        let mut arg = Self::new(name, state_variable);
+        arg.is_in = true;
+        arg
+    }
+
+    pub fn new_out(name: String, state_variable: StateVariable) -> Self {
+        let mut arg = Self::new(name, state_variable);
+        arg.is_out = true;
+        arg
+    }
+
+    pub fn new_in_out(name: String, state_variable: StateVariable) -> Self {
+        let mut arg = Self::new(name, state_variable);
+        arg.is_in = true;
+        arg.is_out = true;
+        arg
+    }
+
+    pub fn state_variable(&self) -> &StateVariable {
+        &self.state_variable
+    }
+
+    pub fn is_in(&self) -> bool {
+        self.is_in
+    }
+
+    pub fn is_out(&self) -> bool {
+        self.is_out
+    }
+}
+
+/// Fabrique un <argument> complet avec ses sous-éléments
+fn make_argument_elem(name: &str, direction: &str, state_var_name: &str) -> Element {
+    let mut arg = Element::new("argument");
+
+    let mut name_elem = Element::new("name");
+    name_elem.children.push(XMLNode::Text(name.to_string()));
+
+    let mut dir_elem = Element::new("direction");
+    dir_elem.children.push(XMLNode::Text(direction.to_string()));
+
+    let mut rel_elem = Element::new("relatedStateVariable");
+    rel_elem
+        .children
+        .push(XMLNode::Text(state_var_name.to_string()));
+
+    arg.children.push(XMLNode::Element(name_elem));
+    arg.children.push(XMLNode::Element(dir_elem));
+    arg.children.push(XMLNode::Element(rel_elem));
+
+    arg
+}
diff --git a/pmoupnp/src/actions/errors.rs b/pmoupnp/src/actions/errors.rs
new file mode 100644
index 00000000..c4ab8443
--- /dev/null
+++ b/pmoupnp/src/actions/errors.rs
@@ -0,0 +1,19 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum ActionError {
+    #[error("Action error: {0}")]
+    GeneralError(String),
+    
+    #[error("Argument error: {0}")]
+    ArgumentError(String),
+    
+    #[error("Set operation error: {0}")]
+    SetError(String),
+}
+
+impl From<std::io::Error> for ActionError {
+    fn from(err: std::io::Error) -> Self {
+        ActionError::GeneralError(format!("IO error: {}", err))
+    }
+}
\ No newline at end of file
diff --git a/pmoupnp/src/actions/mod.rs b/pmoupnp/src/actions/mod.rs
new file mode 100644
index 00000000..9a765134
--- /dev/null
+++ b/pmoupnp/src/actions/mod.rs
@@ -0,0 +1,48 @@
+mod errors;
+
+mod action_methods;
+mod action_instance;
+mod action_set_methods;
+mod action_instance_set;
+mod argument;
+mod arg_set_methods;
+
+
+use std::collections::HashMap;
+use crate::{state_variables::StateVariable, UpnpObjectType};
+
+
+#[derive(Debug, Clone)]
+struct Action {
+    object: UpnpObjectType,
+    arguments: ArgumentSet,
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct ActionSet {
+    actions: HashMap<String, Action>,
+}
+
+#[derive(Debug, Clone)]
+pub struct ActionInstance {
+    object: UpnpObjectType,
+    model: Action,
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct ActionInstanceSet {
+    instances: HashMap<String, ActionInstance>,
+}
+
+#[derive(Debug, Clone)]
+pub struct Argument {
+    object: UpnpObjectType,
+    state_variable: StateVariable,
+    is_in: bool,
+    is_out: bool,
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct ArgumentSet {
+    arguments: HashMap<String, Argument>,
+}
diff --git a/pmoupnp/src/lib.rs b/pmoupnp/src/lib.rs
index 63ce81fa..8a2480a6 100644
--- a/pmoupnp/src/lib.rs
+++ b/pmoupnp/src/lib.rs
@@ -4,10 +4,11 @@ pub mod server;
 pub mod state_variables;
 pub mod value_ranges;
 pub mod variable_types;
+pub mod actions;
 
-pub use crate::object_trait::UpnpObject;
+pub use crate::object_trait::{UpnpXml,UpnpObject};
 
-#[derive(Clone)]
+#[derive(Debug,Clone)]
 pub struct UpnpObjectType {
     name: String,
     object_type: String,
diff --git a/pmoupnp/src/object_trait.rs b/pmoupnp/src/object_trait.rs
index 1c59c3f7..c18dea2a 100644
--- a/pmoupnp/src/object_trait.rs
+++ b/pmoupnp/src/object_trait.rs
@@ -2,18 +2,8 @@ use xmltree::{Element, EmitterConfig};
 
 use crate::UpnpObjectType;
 
-pub trait UpnpObject {
-    fn as_upnp_object_type(&self) -> &UpnpObjectType;
+pub trait UpnpXml {
     fn to_xml_element(&self) -> Element;
-
-    fn get_name(&self) -> &String {
-        return &self.as_upnp_object_type().name;
-    }
-
-    fn get_object_type(&self) -> &String {
-        &self.as_upnp_object_type().object_type
-    }
-
     fn to_xml(&self) -> String {
         let elem = self.to_xml_element();
 
@@ -35,3 +25,16 @@ pub trait UpnpObject {
         xml_string
     }
 }
+pub trait UpnpObject : UpnpXml {
+    fn as_upnp_object_type(&self) -> &UpnpObjectType;
+
+    fn get_name(&self) -> &String {
+        return &self.as_upnp_object_type().name;
+    }
+
+    fn get_object_type(&self) -> &String {
+        &self.as_upnp_object_type().object_type
+    }
+
+
+}
diff --git a/pmoupnp/src/state_variables/instance_methods.rs b/pmoupnp/src/state_variables/instance_methods.rs
index 0e9093a6..b5d76ba8 100644
--- a/pmoupnp/src/state_variables/instance_methods.rs
+++ b/pmoupnp/src/state_variables/instance_methods.rs
@@ -3,6 +3,7 @@ use xmltree::Element;
 
 use crate::{
     UpnpObject, UpnpObjectType,
+    object_trait::UpnpXml,
     state_variables::{StateVarInstance, StateVariable, UpnpVariable},
     variable_types::StateValue,
 };
@@ -13,14 +14,16 @@ impl UpnpVariable for StateVarInstance {
     }
 }
 
+impl UpnpXml for StateVarInstance {
+    fn to_xml_element(&self) -> Element {
+        self.get_definition().to_xml_element()
+    }
+}
+
 impl UpnpObject for StateVarInstance {
     fn as_upnp_object_type(&self) -> &UpnpObjectType {
         return &self.object;
     }
-
-    fn to_xml_element(&self) -> Element {
-        self.get_definition().to_xml_element()
-    }
 }
 
 impl StateVarInstance {
diff --git a/pmoupnp/src/state_variables/mod.rs b/pmoupnp/src/state_variables/mod.rs
index f45fc51b..be971f7a 100644
--- a/pmoupnp/src/state_variables/mod.rs
+++ b/pmoupnp/src/state_variables/mod.rs
@@ -1,6 +1,7 @@
 mod errors;
 mod instance_methods;
 mod variable_methods;
+mod var_set_methods;
 mod variable_trait;
 
 use std::{
@@ -44,6 +45,11 @@ pub struct StateVariable {
     marshal: Option<ValueSerializer>,
 }
 
+#[derive(Debug, Default, Clone)]
+pub struct StateVariableSet {
+    instances: HashMap<String, StateVariable>,
+}
+
 pub struct StateVarInstance {
     object: UpnpObjectType,
     definition: StateVariable,
diff --git a/pmoupnp/src/state_variables/var_set_methods.rs b/pmoupnp/src/state_variables/var_set_methods.rs
new file mode 100644
index 00000000..85113128
--- /dev/null
+++ b/pmoupnp/src/state_variables/var_set_methods.rs
@@ -0,0 +1,34 @@
+use std::collections::HashMap;
+
+use crate::{state_variables::{StateVariable, StateVariableSet}, UpnpObject};
+
+impl StateVariableSet {
+    pub fn new() -> Self {
+        Self {
+            instances: HashMap::new(),
+        }
+    }
+
+    pub fn insert(&mut self, instance: StateVariable) {
+        self.instances.insert(instance.get_name().clone(), instance);
+    }
+
+    pub fn contains(&self, name: &str) -> bool {
+        self.instances.contains_key(name)
+    }
+
+    pub fn get(&self, name: &str) -> Option<&StateVariable> {
+        self.instances.get(name)
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &StateVariable> {
+        self.instances.values()
+    }
+
+    pub fn all(&self) -> Vec<&StateVariable> {
+        self.instances.values().collect()
+    }
+
+
+}
+
diff --git a/pmoupnp/src/state_variables/variable_methods.rs b/pmoupnp/src/state_variables/variable_methods.rs
index a78ccd0c..838709d5 100644
--- a/pmoupnp/src/state_variables/variable_methods.rs
+++ b/pmoupnp/src/state_variables/variable_methods.rs
@@ -1,25 +1,16 @@
 use std::{
-    collections::HashMap,
-    sync::{Arc, RwLock},
+    collections::HashMap, fmt, sync::{Arc, RwLock}
 };
 
 use xmltree::{Element, XMLNode};
 
 use crate::{
-    UpnpObject, UpnpObjectType,
-    state_variables::{
-        StateConditionFunc, StateVariable, StringValueParser, ValueSerializer,
-        variable_trait::UpnpVariable,
-    },
-    value_ranges::ValueRange,
-    variable_types::{StateValue, StateValueError, StateVarType, UpnpVarType},
+    object_trait::UpnpXml, state_variables::{
+        variable_trait::UpnpVariable, StateConditionFunc, StateVariable, StringValueParser, ValueSerializer
+    }, value_ranges::ValueRange, variable_types::{StateValue, StateValueError, StateVarType, UpnpVarType}, UpnpObject, UpnpObjectType
 };
 
-impl UpnpObject for StateVariable {
-    fn as_upnp_object_type(&self) -> &UpnpObjectType {
-        return &self.object;
-    }
-
+impl UpnpXml for StateVariable  {
     fn to_xml_element(&self) -> Element {
         // Création de l'élément racine <stateVariable>
         let mut root = Element::new("stateVariable");
@@ -91,6 +82,13 @@ impl UpnpObject for StateVariable {
 
         root
     }
+
+}
+
+impl UpnpObject for StateVariable {
+    fn as_upnp_object_type(&self) -> &UpnpObjectType {
+        return &self.object;
+    }
 }
 
 impl Clone for StateVariable {
@@ -133,6 +131,37 @@ impl Clone for StateVariable {
     }
 }
 
+impl fmt::Debug for StateVariable {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("StateVariable")
+            .field("object", &self.object)
+            .field("value_type", &self.value_type)
+            .field("step", &self.step)
+            .field("modifiable", &self.modifiable)
+            .field(
+                "event_conditions",
+                &format_args!(
+                    "len={}",
+                    self.event_conditions.read().map(|m| m.len()).unwrap_or(0)
+                ),
+            )
+            .field("description", &self.description)
+            .field("default_value", &self.default_value)
+            .field("value_range", &self.value_range)
+            .field(
+                "allowed_values",
+                &format_args!(
+                    "len={}",
+                    self.allowed_values.read().map(|v| v.len()).unwrap_or(0)
+                ),
+            )
+            .field("send_events", &self.send_events)
+            .field("parse", &self.parse.as_ref().map(|_| "Some(StringValueParser)").unwrap_or("None"))
+            .field("marshal", &self.marshal.as_ref().map(|_| "Some(ValueSerializer)").unwrap_or("None"))
+            .finish()
+    }
+}
+
 impl UpnpVarType for StateVariable {
     fn as_state_var_type(&self) -> StateVarType {
         self.value_type // utilise ton From<&StateValue> existant