diff --git a/vm/src/obj/objlist.rs b/vm/src/obj/objlist.rs
index 0afb44e39..d27593ebe 100644
--- a/vm/src/obj/objlist.rs
+++ b/vm/src/obj/objlist.rs
@@ -145,9 +145,9 @@ impl PyListRef {
     }
 
     fn iadd(self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        if objtype::isinstance(&other, &vm.ctx.list_type()) {
-            let e = get_elements_list(&other).clone();
-            self.elements.borrow_mut().extend_from_slice(&e);
+        if let Ok(new_elements) = vm.extract_elements(&other) {
+            let mut e = new_elements;
+            self.elements.borrow_mut().append(&mut e);
             Ok(self.into_object())
         } else {
             Ok(vm.ctx.not_implemented())