diff --git a/vm/src/obj/objweakproxy.rs b/vm/src/obj/objweakproxy.rs
index 735670f4e..5d4f68d9d 100644
--- a/vm/src/obj/objweakproxy.rs
+++ b/vm/src/obj/objweakproxy.rs
@@ -1,9 +1,10 @@
 use super::objweakref::PyWeak;
 use crate::function::OptionalArg;
 use crate::obj::objtype::PyClassRef;
-use crate::pyobject::{PyContext, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
 use crate::vm::VirtualMachine;
 
+#[pyclass]
 #[derive(Debug)]
 pub struct PyWeakProxy {
     weak: PyWeak,
@@ -17,21 +18,27 @@ impl PyValue for PyWeakProxy {
 
 pub type PyWeakProxyRef = PyRef<PyWeakProxy>;
 
-impl PyWeakProxyRef {
-    // TODO callbacks
+#[pyimpl]
+impl PyWeakProxy {
+    // TODO: callbacks
+    #[pymethod(name = "__new__")]
     fn create(
         cls: PyClassRef,
         referent: PyObjectRef,
-        _callback: OptionalArg<PyObjectRef>,
+        callback: OptionalArg<PyObjectRef>,
         vm: &VirtualMachine,
-    ) -> PyResult<Self> {
+    ) -> PyResult<PyWeakProxyRef> {
+        if callback.is_present() {
+            panic!("Passed a callback to weakproxy, but weakproxy does not yet support proxies.");
+        }
         PyWeakProxy {
             weak: PyWeak::downgrade(&referent),
         }
         .into_ref_with_type(vm, cls)
     }
 
-    fn getattr(self, attr_name: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+    #[pymethod(name = "__getattr__")]
+    fn getattr(&self, attr_name: PyObjectRef, vm: &VirtualMachine) -> PyResult {
         match self.weak.upgrade() {
             Some(obj) => vm.get_attribute(obj, attr_name),
             None => Err(vm.new_exception(
@@ -40,11 +47,19 @@ impl PyWeakProxyRef {
             )),
         }
     }
+
+    #[pymethod(name = "__setattr__")]
+    fn setattr(&self, attr_name: PyObjectRef, value: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+        match self.weak.upgrade() {
+            Some(obj) => vm.set_attr(&obj, attr_name, value),
+            None => Err(vm.new_exception(
+                vm.ctx.exceptions.reference_error.clone(),
+                "weakly-referenced object no longer exists".to_string(),
+            )),
+        }
+    }
 }
 
 pub fn init(context: &PyContext) {
-    extend_class!(context, &context.weakproxy_type, {
-        "__new__" => context.new_rustfunc(PyWeakProxyRef::create),
-        "__getattr__" => context.new_rustfunc(PyWeakProxyRef::getattr),
-    });
+    PyWeakProxy::extend_class(&context, &context.weakproxy_type);
 }