Fix PyNamespace constructor

vm/src/obj/objnamespace.rs

@@ -11,6 +11,7 @@ use crate::vm::VirtualMachine;
 pub struct PyNamespace;
 
 impl PyValue for PyNamespace {
+    const HAVE_DICT: bool = true;
     fn class(vm: &VirtualMachine) -> PyClassRef {
         vm.ctx.namespace_type()
     }
@@ -18,12 +19,13 @@ impl PyValue for PyNamespace {
 
 #[pyimpl]
 impl PyNamespace {
-    #[pymethod(name = "__init__")]
-    fn init(zelf: PyRef<Self>, kwargs: KwArgs, vm: &VirtualMachine) -> PyResult<()> {
+    #[pyslot(new)]
+    fn tp_new(cls: PyClassRef, kwargs: KwArgs, vm: &VirtualMachine) -> PyResult<PyRef<Self>> {
+        let zelf = PyNamespace.into_ref_with_type(vm, cls)?;
         for (name, value) in kwargs.into_iter() {
             vm.set_attr(zelf.as_object(), name, value)?;
         }
-        Ok(())
+        Ok(zelf)
     }
 }