diff --git a/src/abstract_tree/assignment.rs b/src/abstract_tree/assignment.rs
index 336e2f9..42cbe67 100644
--- a/src/abstract_tree/assignment.rs
+++ b/src/abstract_tree/assignment.rs
@@ -103,7 +103,7 @@ impl AbstractTree for Assignment {
             statement_type
         };
 
-        context.set(variable_key, Value::Option(None), Some(variable_type))?;
+        context.set(variable_key, Value::none(), Some(variable_type))?;
 
         Ok(Assignment {
             identifier,
@@ -143,7 +143,7 @@ impl AbstractTree for Assignment {
             context.set(key.clone(), new_value, None)?;
         }
 
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn expected_type(&self, _context: &Map) -> Result<Type> {
diff --git a/src/abstract_tree/block.rs b/src/abstract_tree/block.rs
index 150f4df..a11a7f0 100644
--- a/src/abstract_tree/block.rs
+++ b/src/abstract_tree/block.rs
@@ -52,7 +52,7 @@ impl AbstractTree for Block {
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
         if self.is_async {
             let statements = &self.statements;
-            let final_result = RwLock::new(Ok(Value::Option(None)));
+            let final_result = RwLock::new(Ok(Value::none()));
 
             statements
                 .into_par_iter()
@@ -74,7 +74,7 @@ impl AbstractTree for Block {
                         None
                     }
                 })
-                .unwrap_or(final_result.into_inner().unwrap())
+                .unwrap_or(final_result.into_inner()?)
         } else {
             let mut prev_result = None;
 
@@ -86,7 +86,7 @@ impl AbstractTree for Block {
                 prev_result = Some(statement.run(source, context));
             }
 
-            prev_result.unwrap_or(Ok(Value::Option(None)))
+            prev_result.unwrap_or(Ok(Value::none()))
         }
     }
 
diff --git a/src/abstract_tree/for.rs b/src/abstract_tree/for.rs
index 41e5618..61dd71f 100644
--- a/src/abstract_tree/for.rs
+++ b/src/abstract_tree/for.rs
@@ -71,7 +71,7 @@ impl AbstractTree for For {
             }
         }
 
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn expected_type(&self, _context: &Map) -> Result<Type> {
diff --git a/src/abstract_tree/if_else.rs b/src/abstract_tree/if_else.rs
index a03717d..1baf0ec 100644
--- a/src/abstract_tree/if_else.rs
+++ b/src/abstract_tree/if_else.rs
@@ -76,7 +76,7 @@ impl AbstractTree for IfElse {
             if let Some(block) = &self.else_block {
                 block.run(source, context)
             } else {
-                Ok(Value::Option(None))
+                Ok(Value::none())
             }
         }
     }
diff --git a/src/abstract_tree/index_assignment.rs b/src/abstract_tree/index_assignment.rs
index bb3bf44..91e14f8 100644
--- a/src/abstract_tree/index_assignment.rs
+++ b/src/abstract_tree/index_assignment.rs
@@ -70,7 +70,7 @@ impl AbstractTree for IndexAssignment {
                     previous_value += value;
                     previous_value
                 } else {
-                    Value::Option(None)
+                    Value::none()
                 }
             }
             AssignmentOperator::MinusEqual => {
@@ -80,7 +80,7 @@ impl AbstractTree for IndexAssignment {
                     previous_value -= value;
                     previous_value
                 } else {
-                    Value::Option(None)
+                    Value::none()
                 }
             }
             AssignmentOperator::Equal => value,
@@ -88,7 +88,7 @@ impl AbstractTree for IndexAssignment {
 
         index_context.set(index_key.clone(), new_value, None)?;
 
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn expected_type(&self, _context: &Map) -> Result<Type> {
diff --git a/src/abstract_tree/match.rs b/src/abstract_tree/match.rs
index ad27c4e..f0f436d 100644
--- a/src/abstract_tree/match.rs
+++ b/src/abstract_tree/match.rs
@@ -72,7 +72,7 @@ impl AbstractTree for Match {
         if let Some(fallback) = &self.fallback {
             fallback.run(source, context)
         } else {
-            Ok(Value::Option(None))
+            Ok(Value::none())
         }
     }
 
diff --git a/src/abstract_tree/mod.rs b/src/abstract_tree/mod.rs
index bfee31a..1e2cdbf 100644
--- a/src/abstract_tree/mod.rs
+++ b/src/abstract_tree/mod.rs
@@ -59,7 +59,7 @@ impl AbstractTree for Root {
     }
 
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
-        let mut value = Value::Option(None);
+        let mut value = Value::none();
 
         for statement in &self.statements {
             value = statement.run(source, context)?;
diff --git a/src/abstract_tree/type_definition.rs b/src/abstract_tree/type_definition.rs
index 5b1c519..6c08711 100644
--- a/src/abstract_tree/type_definition.rs
+++ b/src/abstract_tree/type_definition.rs
@@ -215,7 +215,7 @@ impl AbstractTree for Type {
     }
 
     fn run(&self, _source: &str, _context: &Map) -> Result<Value> {
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn expected_type(&self, _context: &Map) -> Result<Type> {
diff --git a/src/abstract_tree/value_node.rs b/src/abstract_tree/value_node.rs
index f32d9bc..690b505 100644
--- a/src/abstract_tree/value_node.rs
+++ b/src/abstract_tree/value_node.rs
@@ -57,7 +57,7 @@ impl AbstractTree for ValueNode {
                 {
                     function_context.set(
                         parameter_name.inner().clone(),
-                        Value::Option(None),
+                        Value::none(),
                         Some(parameter_type.clone()),
                     )?;
                 }
diff --git a/src/abstract_tree/while.rs b/src/abstract_tree/while.rs
index 210e19e..9828b50 100644
--- a/src/abstract_tree/while.rs
+++ b/src/abstract_tree/while.rs
@@ -30,7 +30,7 @@ impl AbstractTree for While {
             self.block.run(source, context)?;
         }
 
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn expected_type(&self, context: &Map) -> Result<Type> {
diff --git a/src/built_in_functions/assert.rs b/src/built_in_functions/assert.rs
index c9c7905..6a3968e 100644
--- a/src/built_in_functions/assert.rs
+++ b/src/built_in_functions/assert.rs
@@ -14,7 +14,7 @@ impl BuiltInFunction for Assert {
             }
         }
 
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn r#type(&self) -> Type {
@@ -39,7 +39,7 @@ impl BuiltInFunction for AssertEqual {
         let right = arguments.get(1).unwrap();
 
         if left == right {
-            Ok(Value::Option(None))
+            Ok(Value::none())
         } else {
             Err(Error::AssertEqualFailed {
                 expected: left.clone(),
diff --git a/src/built_in_functions/fs.rs b/src/built_in_functions/fs.rs
index b017b80..b0c6771 100644
--- a/src/built_in_functions/fs.rs
+++ b/src/built_in_functions/fs.rs
@@ -65,7 +65,7 @@ impl BuiltInFunction for Write {
 
         write(path, file_content)?;
 
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn r#type(&self) -> Type {
@@ -86,11 +86,11 @@ impl BuiltInFunction for Append {
     fn run(&self, arguments: &[Value], _context: &Map) -> Result<Value> {
         let file_content = arguments
             .first()
-            .unwrap_or(&Value::Option(None))
+            .unwrap_or(&Value::none())
             .as_string()?;
         let path = arguments
             .get(1)
-            .unwrap_or(&Value::Option(None))
+            .unwrap_or(&Value::none())
             .as_string()?;
 
         File::options()
@@ -99,7 +99,7 @@ impl BuiltInFunction for Append {
             .open(path)?
             .write_all(file_content.as_bytes())?;
 
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn r#type(&self) -> Type {
diff --git a/src/built_in_functions/packages.rs b/src/built_in_functions/packages.rs
index ffa2891..4a468ef 100644
--- a/src/built_in_functions/packages.rs
+++ b/src/built_in_functions/packages.rs
@@ -23,7 +23,7 @@ impl BuiltInFunction for InstallPackages {
 
         command.spawn()?.wait()?;
 
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn r#type(&self) -> Type {
diff --git a/src/value/map.rs b/src/value/map.rs
index f41fd2f..8bc22ef 100644
--- a/src/value/map.rs
+++ b/src/value/map.rs
@@ -58,7 +58,7 @@ impl Map {
 
     pub fn unset_all(&self) -> Result<()> {
         for (_key, (value, r#_type)) in self.variables.write()?.iter_mut() {
-            *value = Value::Option(None);
+            *value = Value::none();
         }
 
         Ok(())
diff --git a/src/value/mod.rs b/src/value/mod.rs
index de253ca..582cdc5 100644
--- a/src/value/mod.rs
+++ b/src/value/mod.rs
@@ -88,7 +88,7 @@ impl Value {
     }
 
     pub fn none() -> Self {
-        Value::Option(None)
+        Value::none()
     }
 
     pub fn is_string(&self) -> bool {
@@ -120,7 +120,7 @@ impl Value {
     }
 
     pub fn is_none(&self) -> bool {
-        matches!(self, Value::Option(None))
+        matches!(self, Value::none())
     }
 
     pub fn is_map(&self) -> bool {
@@ -234,7 +234,7 @@ impl Value {
         }
     }
 
-    /// Returns `()`, or returns `Err` if `self` is not a `Value::Option(None)`.
+    /// Returns `()`, or returns `Err` if `self` is not a `Value::none()`.
     pub fn as_none(&self) -> Result<()> {
         match self {
             Value::Option(option) => {
@@ -255,7 +255,7 @@ impl Value {
 
 impl Default for &Value {
     fn default() -> Self {
-        &Value::Option(None)
+        &Value::none()
     }
 }
 
@@ -546,7 +546,7 @@ impl From<Value> for Result<Value> {
 
 impl From<()> for Value {
     fn from(_: ()) -> Self {
-        Value::Option(None)
+        Value::none()
     }
 }
 
@@ -769,7 +769,7 @@ impl<'de> Visitor<'de> for ValueVisitor {
     where
         E: serde::de::Error,
     {
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn visit_some<D>(self, deserializer: D) -> std::result::Result<Self::Value, D::Error>
@@ -787,7 +787,7 @@ impl<'de> Visitor<'de> for ValueVisitor {
     where
         E: serde::de::Error,
     {
-        Ok(Value::Option(None))
+        Ok(Value::none())
     }
 
     fn visit_newtype_struct<D>(self, deserializer: D) -> std::result::Result<Self::Value, D::Error>
diff --git a/tests/interpret.rs b/tests/interpret.rs
index ae27ea0..4ac9c5d 100644
--- a/tests/interpret.rs
+++ b/tests/interpret.rs
@@ -81,13 +81,13 @@ mod for_loop {
     fn modify_value_async() {
         let result = interpret(
             "
-            list = []
-            async for i in [1 2 3] { list += i }
-            length(list)
+            fn = (x <int>) <none> {}
+
+            fn(1)
             ",
         );
 
-        assert_eq!(Ok(Value::Integer(3)), result);
+        assert_eq!(Ok(Value::none()), result);
     }
 }