Implement __func__ in @staticmethod

Author: ChJR

vm/src/builtins/staticmethod.rs

@@ -68,6 +68,11 @@ impl PyStaticMethod {
 
 #[pyimpl(with(Callable, GetDescriptor, Constructor), flags(BASETYPE, HAS_DICT))]
 impl PyStaticMethod {
+    #[pyproperty(magic)]
+    fn func(&self) -> PyObjectRef {
+        self.callable.clone()
+    }
+
     #[pyproperty(magic)]
     fn isabstractmethod(&self, vm: &VirtualMachine) -> PyObjectRef {
         match vm.get_attribute_opt(self.callable.clone(), "__isabstractmethod__") {