review: make value_of internal and remove unused function

01.workspace/heave/src/str/entity.rs

@@ -42,31 +42,13 @@ impl O {
         }
         self
     }
-    pub fn value_of(&self, id: &str) -> Option<&Value> {
+    pub(crate) fn value_of(&self, id: &str) -> Option<&Value> {
         let attribute = self.attributes.get(id);
         match attribute {
             None => None,
             Some(attribute) => Some(&attribute.value),
         }
     }
-    pub fn set(&mut self, id: &str, value: impl Into<Value>) -> Option<Value> {
-        let attribute = Attribute::new(id, value);
-        let previous_attribute = self.attributes.insert(attribute.id.clone(), attribute);
-        match previous_attribute {
-            None => None,
-            Some(attribute) => Some(attribute.value),
-        }
-    }
-    pub fn unset(&mut self, id: &str) -> Option<Value> {
-        let attribute = self.attributes.remove(id);
-        match attribute {
-            None => None,
-            Some(attribute) => Some(attribute.value),
-        }
-    }
-    pub fn has_attribute(&self, id: &str) -> bool {
-        self.attributes.contains_key(id)
-    }
     pub fn unwrap<T>(&self, id: &str) -> T
     where
         T: From<Value>,

01.workspace/heave/src/tst/intended_use.rs

@@ -27,15 +27,12 @@ mod tests {
     }
     impl From<Product> for Entity {
         fn from(value: Product) -> Self {
-            let mut entity = Entity::new::<Product>()
+            Entity::new::<Product>()
                 .with_id(&value.id)
                 .with_attribute("name", value.name)
                 .with_attribute("price", value.price)
-                .with_attribute("in_stock", value.in_stock);
-            if let Some(model) = value.model {
-                entity.set("model", model);
-            }
-            entity
+                .with_attribute("in_stock", value.in_stock)
+                .with_opt_attribute("model", value.model)
         }
     }
     #[test]