bpo-41870: Avoid the test when nargs=0 (GH-22462)

diff --git a/Objects/boolobject.c b/Objects/boolobject.c
index ab7669c..b786966 100644
--- a/Objects/boolobject.c
+++ b/Objects/boolobject.c
@@ -72,9 +72,9 @@
     assert(PyType_Check(type));
     if (nargs) {
         ok = PyObject_IsTrue(args[0]);
-    }
-    if (ok < 0) {
-        return NULL;
+        if (ok < 0) {
+            return NULL;
+        }
     }
     return PyBool_FromLong(ok);
 }