diff --git a/src/ZodSchemaClass.ts b/src/ZodSchemaClass.ts
index 72d10c9..50fb98a 100644
--- a/src/ZodSchemaClass.ts
+++ b/src/ZodSchemaClass.ts
@@ -1,4 +1,4 @@
-import { Trait, TraitExpressionBuilder } from "@thilawyn/traitify-ts"
+import { Trait, TraitExpression, TraitExpressionBuilder } from "@thilawyn/traitify-ts"
 import { AbstractClass } from "type-fest"
 import { JsonifiableObject } from "type-fest/source/jsonifiable"
 import { z } from "zod"
@@ -15,20 +15,18 @@ export class ZodSchemaClassBuilder<
     const Traits extends Trait<any, any, any, any>[],
 >
 extends TraitExpressionBuilder<Superclass, Traits> {
-    // extends<
-    //     This  extends ZodSchemaClassBuilder<
-    //         typeof TraitExpression.NullSuperclass,  // Ensures `extends` can only be called when the expression does not have a superclass
-    //         Traits
-    //     >,
-    //     Super extends AbstractClass<object, []>,
-    // >(
-    //     this:        This,
-    //     superclass:  Super,
-    // ) {
-    //     return new ZodSchemaClassBuilder(
-    //         this.expressionBuilder.extends(superclass)
-    //     )
-    // }
+    extends<
+        Super extends AbstractClass<object>
+    >(
+        //                                        \/ Ensures `extends` can only be called once at the beginning
+        this:        ZodSchemaClassBuilder<typeof TraitExpression.NullSuperclass, Traits>,
+        superclass:  Super,
+    ) {
+        return new ZodSchemaClassBuilder(
+            superclass,
+            this.expressionTraits,
+        )
+    }
 
     schema<
         Superclass        extends AbstractClass<object, []> & { schema?: never, defaultValues?: never },