diff --git a/01.workspace/heave/src/str/entity.rs b/01.workspace/heave/src/str/entity.rs
index 1cb278e..ca84d8e 100644
--- a/01.workspace/heave/src/str/entity.rs
+++ b/01.workspace/heave/src/str/entity.rs
@@ -27,8 +27,11 @@ impl O {
         self.id = id.to_string();
         self
     }
-    pub fn with_class(mut self, class: &str) -> Self {
-        self.class = class.to_string();
+    pub fn with_class<T>(mut self) -> Self
+    where
+        T: EAV,
+    {
+        self.class = T::class().to_string();
         self
     }
     pub fn with_ref_date(mut self, ref_date: u64) -> Self {
diff --git a/01.workspace/heave/src/tst/intended_use.rs b/01.workspace/heave/src/tst/intended_use.rs
index a1aecd4..b75faf5 100644
--- a/01.workspace/heave/src/tst/intended_use.rs
+++ b/01.workspace/heave/src/tst/intended_use.rs
@@ -15,7 +15,7 @@ mod tests {
     impl From<Product> for Entity {
         fn from(value: Product) -> Entity {
             Entity::default()
-                .with_class("product")
+                .with_class::<Product>()
                 .with_id(&value.id)
                 .with_attribute("name", value.name)
                 .with_attribute("price", value.price)
diff --git a/01.workspace/heave/src/tst/rusty_budger_use.rs b/01.workspace/heave/src/tst/rusty_budger_use.rs
index 885c4f8..e6a90e4 100644
--- a/01.workspace/heave/src/tst/rusty_budger_use.rs
+++ b/01.workspace/heave/src/tst/rusty_budger_use.rs
@@ -19,7 +19,7 @@ mod tests {
         impl From<OperationToCategory> for Entity {
             fn from(value: OperationToCategory) -> Entity {
                 Entity::default()
-                    .with_class("operation_has_category")
+                    .with_class::<OperationToCategory>()
                     .with_id(&value.id)
                     .with_attribute("operation_id", value.operation_id)
                     .with_attribute("category_id", value.category_id)
@@ -49,7 +49,7 @@ mod tests {
         impl From<Category> for Entity {
             fn from(value: Category) -> Entity {
                 Entity::default()
-                    .with_class("category")
+                    .with_class::<Category>()
                     .with_id(&value.id)
                     .with_attribute("label", value.label)
             }
@@ -79,7 +79,7 @@ mod tests {
         impl From<Operation> for Entity {
             fn from(value: Operation) -> Entity {
                 Entity::default()
-                    .with_class("operation")
+                    .with_class::<Operation>()
                     .with_id(&value.id)
                     .with_attribute("date", value.date)
                     .with_attribute("amount", value.amount)