diff --git a/psutil/tests/__init__.py b/psutil/tests/__init__.py
index e6f0abc35..9108f6feb 100644
--- a/psutil/tests/__init__.py
+++ b/psutil/tests/__init__.py
@@ -1744,7 +1744,7 @@ def is_namedtuple(x):
     f = getattr(t, '_fields', None)
     if not isinstance(f, tuple):
         return False
-    return all(type(n) == str for n in f)
+    return all(type(n) is str for n in f)
 
 
 if POSIX: