setting Sentinel __nonzero__/__bool__ alias and also adding a test for sentinel falsiness

boltons/typeutils.py

@@ -53,8 +53,11 @@ def make_sentinel(name='_MISSING', var_name=None):
             def __reduce__(self):
                 return self.var_name
 
-        def __len__(self):
-            return 0
+        def __nonzero__(self):
+            return False
+
+        __bool__ = __nonzero__
+
     return Sentinel()
 
 

tests/test_typeutils.py

@@ -0,0 +1,7 @@
+
+from boltons.typeutils import make_sentinel
+
+
+def test_sentinel_falsiness():
+    not_set = make_sentinel('not_set')
+    assert not not_set