typo

src/mixin.ts

@@ -44,7 +44,7 @@ function applyMixin(
   }
   const sourceParentClass = Object.getPrototypeOf(sourceClass);
   if (sourceParentClass?.prototype) {
-    applyMixin(sourceParentClass, sourceParentClass, visited);
+    applyMixin(mixedClass, sourceParentClass, visited);
   }
 }