bpo-37483: add _PyObject_CallOneArg() function (#14558)

diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index ee1b5e5..b93ec3d 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -2696,7 +2696,7 @@
         PyObject *event = PyTuple_Pack(2, action, node);
         if (event == NULL)
             return -1;
-        res = _PyObject_FastCall(self->events_append, &event, 1);
+        res = _PyObject_CallOneArg(self->events_append, event);
         Py_DECREF(event);
         if (res == NULL)
             return -1;
@@ -2859,7 +2859,7 @@
     }
 
     if (self->comment_factory) {
-        comment = _PyObject_FastCall(self->comment_factory, &text, 1);
+        comment = _PyObject_CallOneArg(self->comment_factory, text);
         if (!comment)
             return NULL;
 
@@ -3197,7 +3197,7 @@
     if (errmsg == NULL)
         return;
 
-    error = _PyObject_FastCall(st->parseerror_obj, &errmsg, 1);
+    error = _PyObject_CallOneArg(st->parseerror_obj, errmsg);
     Py_DECREF(errmsg);
     if (!error)
         return;
@@ -3260,7 +3260,7 @@
                 (TreeBuilderObject*) self->target, value
                 );
         else if (self->handle_data)
-            res = _PyObject_FastCall(self->handle_data, &value, 1);
+            res = _PyObject_CallOneArg(self->handle_data, value);
         else
             res = NULL;
         Py_XDECREF(res);
@@ -3371,7 +3371,7 @@
         /* shortcut */
         res = treebuilder_handle_data((TreeBuilderObject*) self->target, data);
     else if (self->handle_data)
-        res = _PyObject_FastCall(self->handle_data, &data, 1);
+        res = _PyObject_CallOneArg(self->handle_data, data);
     else
         res = NULL;
 
@@ -3398,7 +3398,7 @@
     else if (self->handle_end) {
         tag = makeuniversal(self, tag_in);
         if (tag) {
-            res = _PyObject_FastCall(self->handle_end, &tag, 1);
+            res = _PyObject_CallOneArg(self->handle_end, tag);
             Py_DECREF(tag);
         }
     }
@@ -3485,7 +3485,7 @@
         if (!prefix)
             return;
 
-        res = _PyObject_FastCall(self->handle_end_ns, &prefix, 1);
+        res = _PyObject_CallOneArg(self->handle_end_ns, prefix);
         Py_DECREF(prefix);
     }
 
@@ -3515,7 +3515,7 @@
         if (!comment)
             return;
 
-        res = _PyObject_FastCall(self->handle_comment, &comment, 1);
+        res = _PyObject_CallOneArg(self->handle_comment, comment);
     }
 
     Py_XDECREF(res);