diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index edce250..9e1b281 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1047,7 +1047,7 @@
             to the underlying mapping */
 
 static PyMethodDef mappingproxy_methods[] = {
-    {"get",       (PyCFunction)mappingproxy_get,        METH_FASTCALL,
+    {"get",       (PyCFunction)(void(*)(void))mappingproxy_get, METH_FASTCALL,
      PyDoc_STR("D.get(k[,d]) -> D[k] if k in D, else d."
                "  d defaults to None.")},
     {"keys",      (PyCFunction)mappingproxy_keys,       METH_NOARGS,